Here's what I would throw out there as criteria for new members.
1. Primarily consultants with 10+ years experience Sage MAS
2. Have 10 or fewer consultants
3. Not in a geographic area where we have a member
4. Maintain the highest standards of ethical behavior
5. Share regularly with the group
6. If we don't hear from new members once in 30 days the membership is de-activated.
7. This is not a lurker group - don't apply unless you expect to regularly participate (see #6)