Send invitation to group from GJ backend

Thank you! that did the trick

However I do not see how to embed in the body, the newly created group reference.
With [group], this does not work.

Thanks in advance,

You want the users usergroup? Don't understand what you're expecting from [group] as no such substitution exists.

Correct, I want the user's usergroup...

There's no substitution for that. A user can have multiple usergroups. You could test for all your usergroups using substitutions I suppose. Example as follows.

[cb:if gids includes "2"]Registered[/cb:if]

Please see the below tutorial for further substitution usage information.

www.joomlapolis.com/support/tutorials/107-use-cases/18353-using-substitutions-throughout-cb

I saw this tutorial, but that does not answer to my problem.

In my case, one user => one and only one usergroup.

At this stage, autoaction sends mails to specific ACL - ok

As I said, I would like in the auto-generated mail, to have an hyperlink of the user's usergroup so anyone from the ACL receiving that mail is able to connect to it.

This is the very last piece that I need, and that will make everything working...

Thanks for your assistance

You can't condition the usergroup. You need to use the Access parameter. You can try conditioning against [gids], but I doubt it'll work. You'd use one of the Contains operators. To display the usergroup in the email you need to use my above suggestion as there's no other way to get the text value of a usergroup through substitutions unless you query for that information using a CB Query Field.