Yes, I think I agree with James that it would be more user-friendly to have a single list of patients–though the distinction would have to be clear in this list, since opening a local record and importing a patient from an MPI have different implications.
One other thing that will have to be handled is duplicates… assumedly, if the MPI is properly populated with all patients, then every patient in the local database would also be in the MPI, but we won’t want to show that patient twice. (Assumedly whether it was the “same” patient would be determined by the primary patient identifier).
However, it would be nice to have the ability to synchronize functionality between the records. For example, if 1) a patient goes to health center A and is registered, and pushed up to the MPI, and then 2) she goes to health center B, she is found in the MPI and imported into health center B’s database, but during registration at health center B she updates her phone number, and finally 3) she returns to health center A… at this point it would be nice to be able to update her phone number locally. This is probably a phase 2 (or 3) feature, however, and might be out of scope of your project… 