Membership / Buddypress groups - assign to user roles

I have a question about Buddypress groups -

I would to like automate the whole process by automatically letting different membership levels have access to different groups.

For example I have a number of private groups for paying members - the problem is that the paying members have to either request access to the groups or I have to invite them to join. Then if they downgrade their membership, they still have access to the private groups and I have to trawl each group kicking non paying members out of the premium groups.

Is there a way to automate this process via the membership plugin or via roles?