开云体育

Dan,

If I interpreted your message correctly, I think the reason you're having problems with this is that you think the users have to opt out of the subgroup, they don't (normally). They have to opt-in, unless if you already manually added all users to the subgroup already after you created it, which -if so- is not the best way of doing this for a general-use subgroup; for a specific-use subgroup like let's say board-of-directors, then yes, you would manually add the necessary folk from the main group, but for general-use subgroups, it's best to create it, set it up as needed, then let the group know about it and let whoever wants to join it.

Anyway, since you want to send an invitation I presume you have not added them manually already, in which case, think of it as sending invitations from a any regular group.

Cheers,
Christos