2005CFmom,
Quite honestly your doctor sounds like he's taken an interest in the CF. I don't see that it would hurt (MORE is always better than less) unless it will be for $$ for you from you for copays. If it is, explain to him that is why you don't want to be seen at both, but if he truely is that interested and wants to further his own education, maybe he'll write off your portion of the copay.
Mark was recently seen by a pulmonologist, so he was a specialist not a FP doc, but he had never had any CF patients. Mark was his first but he wanted to treat him because he was VERY interested. He made phone calls all the time to the local CF center to ask questions, veryify information... just because he was so new, but very interested in a CF case. He has since taken on 3 other CFers and they all love him.