Please use the following code instead.

/**
 * Remove groups from user profile based on member type.
 */
function buddydev_remove_group_based_on_member_types() {
	if ( ! bp_is_user() ) {
		return;
	}

	$user_id = bp_displayed_user_id();

	if ( ! bp_has_member_type( $user_id, 'agent' ) ) {
		bp_core_remove_nav_item( 'groups' );

		$access = bp_core_can_edit_settings();
		$friends_link = bp_displayed_user_domain()? bp_displayed_user_domain() : bp_loggedin_user_domain();
		$friends_link = trailingslashit( $friends_link . bp_get_friends_slug() );
		bp_core_new_subnav_item(array(
			'name'            => __( 'Invitations', 'buddypress' ),
			'slug'            => 'invites',
			'parent_url'      => $friends_link,
			'parent_slug'     => bp_get_friends_slug(),
			'screen_function' => 'buddydev_groups_screen_group_invites',
			'user_has_access' => $access,
			'position'        => 30
		));
		// move the invitations to the friends screen.
	}
}

add_action( 'bp_setup_nav', 'buddydev_remove_group_based_on_member_types', 1001 );

/**
 * Helps us detect screen.
 */
function buddydev_groups_screen_group_invites() {
    add_action( 'groups_screen_group_invites', 'buddydev_load_invite_template' );
	groups_screen_group_invites();
}

/**
 * Load our template.
 */
function buddydev_load_invite_template() {
    add_action( 'bp_template_content', function () {
        bp_get_template_part('members/single/groups/invites');
    });

	bp_core_load_template('members/single/plugins' );
}

/**
 * Change the invite link url for the non 'agent' users.
 *
 * @param string $link original link.
 *
 * @return string
 */
function buddydev_update_group_invite_link( $link ) {
    // for agent, do not break it.
    if ( bp_has_member_type( bp_loggedin_user_id(), 'agent' ) ) {
       return $link;
    }

	global $groups_template;

	if ( empty( $group ) ) {
		$group =& $groups_template->group;
	}

	$friends_url = bp_loggedin_user_domain() . bp_get_friends_slug() .'/invites/';
	$url         = trailingslashit( $friends_url . 'accept/' . $group->id );
	$url         = add_query_arg( array( 'redirect_to' => $friends_url  ), $url );

	//
	return wp_nonce_url( $url, 'groups_accept_invite' );
}

add_filter( 'bp_get_group_accept_invite_link', 'buddydev_update_group_invite_link' );

/**
 * Change the reject link url for the non 'agent' users.
 *
 * @param string $link original link.
 *
 * @return string
 */
function buddydev_update_group_reject_link( $link ) {
    // for agent, do not break it.
    if ( bp_has_member_type( bp_loggedin_user_id(), 'agent' ) ) {
       return $link;
    }

	global $groups_template;

	if ( empty( $group ) ) {
		$group =& $groups_template->group;
	}

	$friends_url = bp_loggedin_user_domain() . bp_get_friends_slug() .'/invites/';
	$url         = trailingslashit( $friends_url . 'reject/' . $group->id );
	$url         = add_query_arg( array( 'redirect_to' => $friends_url ), $url );

	return wp_nonce_url( $url, 'groups_reject_invite' ) ;
}

add_filter( 'bp_get_group_reject_invite_link', 'buddydev_update_group_reject_link' );

/**
 * Remove groups from adminbar based on member type.
 *
 * @param array $nav nav items.
 *
 * @return array
 */
function buddydev_filter_show_hide_groups_in_adminbar( $nav ) {
	if ( ! is_user_logged_in() ) {
		return $nav;
	}

	if ( ! bp_has_member_type( bp_loggedin_user_id(), 'agent' ) ) {
		$nav = array();
	}

	return $nav;
}

add_filter( 'bp_groups_admin_nav', 'buddydev_filter_show_hide_groups_in_adminbar' );

It will work if you try to accept from the Friends->Invites screen.

Problem:-
– I don’t see a way for filtering the link in the email notification.
– You also need code for filtering the link in the local notification(atleast 2 more filters).

Regards
Brajesh

Hi PresPhuture,
Thank you for posting.
Yes, it is possible to control which category/tags are shown

/**
 * Filter the BuddyBlog form settings and limit category/tag inclusion.
 *
 * @param array $settings settings array.
 *
 * @return array
 */
function buddydev_filter_buddyblog_form_settings( $settings ) {

	$tax                        = isset( $settings['tax'] ) ? $settings['tax'] : array();
	$tax['category']['include'] = array( 1, 2, 3 );// category ids to include.
	$tax['post_tag']['include'] = array( 5, 7, 9 );// tag ids to include.

	$settings['tax'] = $tax;

	return $settings;
}

add_filter( 'buddyblog_post_form_settings', 'buddydev_filter_buddyblog_form_settings' );

Please change the ids with your own. It will only list the category tags with those ids. I hope you can modify it form there on.

Hope that helps.

Regards
Brajesh

Hi Ekiz,
I see the problem. You are using ordered list while the code I posted allowed unordered list. I have updated the code to allow ordered list too now

/**
 * Add remove filters to allow more tags.
 */
function buddydev_add_remove_group_desc_filters() {
	remove_filter( 'groups_group_description_before_save', 'wp_filter_kses', 1 );
	add_filter( 'groups_group_description_before_save', 'bp_groups_filter_kses', 1 );
}

add_action( 'bp_loaded', 'buddydev_add_remove_group_desc_filters');

/**
 * Allow extra tags in group description.
 *
 * @param $tags
 *
 * @return mixed
 */
function buddydev_allow_extra_group_desc_tags( $tags ) {
    $tags['ul'] = array();
    $tags['ol'] = array();
    $tags['li'] = array();
    $tags['strong'] = array();
    $tags['b'] = array();
    return $tags;
}
add_filter( 'bp_groups_filter_kses', 'buddydev_allow_extra_group_desc_tags' );

Regards
Brajesh