Yea, I guess whomever you end up hiring to do this will need to understand how callmydoc fits into the whole picture.
In my head I am comparing callmydac to something like Car Wars in the automotive industry (I may be way off on this assumption here).
Car Wars handles all initial inbound calls and has the call logic to understand what needs to happen with the call as indicated by the caller. Once it knows where to send the call Car Wars would simply forward that call to an unpblushed external number that’s configured on the FreePBX backed that connects the caller to the appropriate individuals or group that needs to handle that call.
The trick here is to understand how callmydoc is being used in this environment.