User Limitation

Not sure if I missed anything. I am not an advanced user, but it seems like it applies to single subscription.
FYI, we have two subscriptions; one allows max 100 users per community, and the other allows 500 users. 
How can we implement your solution for both subscription?

It currently is setup to apply to all groups. Add an additional condition as follows to condition the auto actions per group. So you'll need 4 auto actions in total to have different limits for each or to use IF conditions for the join limit, whichever works best for you.

Field: Custom > Value
Custom Value: [var2_id]
Operator: Equal To
Value: GROUP_ID_HERE

Replace GROUP_ID_HERE with the ID of your group from CB GroupJive > Groups.

Please ignore.
The question has been answered in this thread. I missed it. 

Its working now as intended, except one minor issue.
How do I specify the following variables in the "To" field when sending customized emails:
email address of user trying to join the group.
email address of user that owns the group.
Which email address does 'email' (in square brackets) refer to?