Has anyone looked at or (better yet) analyzed acquisition of a Real Estate Brokerage?

I recently got approached by 3 partners who are aging and looking to transition out of a very successful local brokerage. Question is: how to approach the transition stage and generating value once the owners scale back their work.

I'm trying to determine how best to value the business and how growth would occur given the "kill what you eat" nature of brokerages. If you've looked at this space, I'd welcome a short chat. Thanks!