Hi Andrew,
I agree with Jason that there are some nuances to this situation that could make it easy to give wrong advice (I also agree with him that Phil is a brilliant Local SEO consultant and it might be worth your while to reach out to him for some private consultation, during which you can show him the actual business). In the meantime, it's important to remember that Local SEO hinges on physical location. If Business A is located in Dallas and its airport limos operate from within that city, then this is how Google will see your business and it's what dictates what you can build out local listings for. But as to Business A's subcontracting relationships with Businesses B, C and D in other regions of the country, how you handle this in terms of content development would likely center around things like:
-
Whose brand is being used in those other regions? Is it Business A's brand, or the brands of the subcontractors?
-
What is the exact subcontracting relationship?
-
If the brands being used in the other regions aren't Business A's, could it confuse Google/hurt the business to associate it with these regions where there is no physical presence?
You'll want to dig deep into these questions and others (possibly with a consultant) to arrive at a strategy that helps the business instead of hurting it.