Hi,
I have gone through the discussion here :
https://buddydev.com/support/forums/topic/buddypress-multi-network-main-site-users-have-access-to-all-subsites/
and it is not clear if a solution was finally found.

I have a BuddyBoss platform and added the BuddyPress Multi Network.

All users have access to the main site, which is normal.

I have written a small piece of code to list all the subsites on the main site : if the logged-in user is a user of a subsite, the code displays a link to this site URL, else the code displays a link to the register page on the subsite.

PROBLEM : when a site X user clicks on the link to site Y register page (he does not belong to site Y) he is automatically added as a site Y user and goes directly to the homepage.

Please can you clarify for me whether there is a way to prevent this behaviour or not ?

Many thanks,

Olivier