Any Folks with Experience on rollups in the GI Surgery Center Space?

My team has come across a niche group of family-owned GI medical centers. The founding GI physician wants to retire indefinitely post-sale. My initial thoughts are that it will be difficult to replace him. Also, because the target audience is so niche my thoughts on growth would mean rebranding.

Anybody have experience sourcing a GI Physician or starting a GI Physician Group? If so, what was attractive to physicians that you brought on? How could I structure a plan for growth in the GI Space in 3-5 years?