Thank you, i'll mess around with this.Yeah.
There is custom user field criteria within User Group Promotions.
So you would need 3 separate promotions.
One that applies when the choice for that field is "Christian".
One that applies when the choice is "Athiest".
One that applies when "Undecided".
If a user selects two of them, the two corresponding promotions will apply and they will be a member of both groups.
It's then just a case of setting/revoking permissions accordingly on the node for those groups.
What if I only want them to be able to choose one? I obviously dont want someone to be able to choose and be able to see the Atheist group/forum AND the christian goup/forum - I need them to only be able to belong to oneIf a user selects two of them, the two corresponding promotions will apply and they will be a member of both groups.
I really appreciate your help!