I honestly don't know what the process is if you want to change jobs from one HPSA/MUA to another, particularly if they are in different states. In any case, at the time of filing the NIW you provided a letter from state1. I believe (but am not sure) that at a later point you have to provide another letter from the state that your practice continues to be in the public interest. This is where state2 would come into play.
On paper, a hospitalist is a 'physician practicing internal medicine'. It doesn't (yet) require a fellowship and you are taking care of patients (as opposed to growing cells in a petri dish). If you keep everything to 'physician internal medicine', it shouldn't be an issue.
I am not an attorney, so get better advice than mine on this.