Hi Keith,
Thank you for the question.

Implementing Relationship is a complex problem and I am saying this because I had multiple plans to have it for BuddyPress.

Technically, I see a relationship as a connection between two entities where the connection has

– 2 named association(you call it relation) from one person to another(Father->Son, Son->Father)
– constraints

Since a person is added by another person, we know the relation from person 1 -> Person 2 but not the reverse.

There can be multiple strategies to determine the reverse. If we want to automate it, we will need to know the gender of the people involved as well as gender based reverse should be defined for each of the relationship.

Gender is not a standard feature of BuddyPress and that should be taken in account too.

Another simpler strategy will be to let the person being added as a relative choose their own relationship with the person who added it. The issue here is the correctness of the relationship.

We also need to consider the constraints like one to one or one to many relationship. A person can have many children but a person can have only one mother/father.

Keeping this all in account and developing the plugin(with the notifications and all) will take significant amount of time.

I have tried to evaluate the commercial viability of such plan but I did not see much interest in the past(I seem to check only a couple of people looking for it).

Because of all of this, I do not think we will be able to creating something like this in near future.

I regret my inability to currently assist you on this.

Regards
Brajesh

Thank you.