Hello

I can put here a summary of all my topics that are normally feasible   

I have created 2 Joomla users
testHD1 in the joomla group: "GR1 J test" with "GR1 J test access" access
testHD2 in the joomla group: "GR2 J test" with access "GR2 J test access".

1/ The main use will be the Sociable discussion group and member search by Joomla custom fields, hence the importance of v1.2.1 (https://www.corejoomla.com/forum/support/sociable/17571-use-joomla-member-profile.html) and link between sociable group and addition to the access of the corresponding Joomla group!

2/ There could be dozens of separate discussion groups.
Each member has access to one or more discussion groups.
I have not been able to implement the visibility of the group by the member either.
https://www.corejoomla.com/forum/support/sociable/17566-groupe-visibility.html

3/ Registration on the site is not direct/visible/selectable. It is a facilitator/friend who sends a url (linked to the group) that will allow you to register on the site and directly in the facilitator/friend's group and later in other public groups.
https://www.corejoomla.com/forum/support/sociable/17567-join-a-group-by-url.html
Again if you could set this up or tell me step by step how to do it?

4/ Does one of my requests depend on:
https://www.corejoomla.com/suggest-an-idea/sociable/to-add-or-remove-acl-group.html

Regards