When you run the Prescription Drug Plan Finder, the results are driven by
cost, formulary, and preferred pharmacy. So if someone puts in his favorite
pharmacy, he'll only see plans that contract with that pharmacy.

The bigger problem is going to be the formularies, which may lock people who
take certain drugs out of plans that contract with their favorite pharmacy
(unless they want to pay full retail for some expensive drugs). I just ran a
check of the plans in my state and most seem to work with the well known
pharmacies. But the formularies vary widely.

Yes, it may be a "mess."