I applied to 2 specialties, decided not to do one but accepted interviews at the same hospital at about 3 or 4 places. As it turned out I cancelled those interviews for both specialties anyway as I had better interviews but I would have gone to both if I still hadn't decided at that point. some people do say that its dangerous to do so and I would try to have made a decision by the time you interview. I think some of my LOR actually made reference to the other specialty, but I don't think it hurt me too much. I just told them that I was deciding between the two at the time the letters were written and that I had since decided and cancelled all interviews, which was true.
some of the hospitals i was interested in had both transitional and prelim medicine programs. i applied to both programs and sometimes received interviews for both, sometimes received interviews for only one. for those that i was offered both interviews, some were combined (or used my interview with one of the programs for the other) while some were two completely separate affairs.
of course, both transitional and prelim programs know that you're only going to be there a year and are really just going to be an extra body for them. i don't know how people managed applying to/interview for 2 disparate programs at the same institution.
I applied to both Pediatrics and Combined Medicine-Pediatrics. For the most part, I was honest and let them know I was applying to both. I didn't want to look bad as if I was trying to be sneaky. Plus, most program directors for these two specialties usually oversee both programs, so they were bound to find out anyway. It never seemed to be an issue. In fact, I think it showed that was I really interested in their school/hospital.
However, this might not be the same if someone were to apply to both FP and OB/GYN, for example. Since peds and med-peds are pretty much similar, most PD's know that applicants applying to med-peds might fall back on categorical peds because there are fewer spots for med-peds around the country. This helps increase your chances.
I'm sure someone else can shed light on this who has been through it and applied to two competely different specialties. I do remember a lot of people advising me in the beginning (I was initially going to go for OB/GYN and Peds) that it's not a good idea to apply to the same hospital. PD's and residents talk and you're bound to get "caught". It may make you seem like your wishy -washy and not serious about one specialty. You could take the chance though, as most PD's may not communicate with eachother.
Initially I applied to UC Irvine for both Peds and OB/GYN and no one noticed. I do remember being terrified on my interview day for Peds that the OB/GYN residents and/or PD would see me and wonder what the heck I was doing! Of course in the end I only ranked Peds so it was never an issue. Perhaps if I had ranked both, word may have leaked out...
I hope this helps, I would talk to residents who may have done the same thing and actually ranked two different specialties. I remember meeting quite a few residents on my rotations who did this and it never seemed to be an issue. The only thing they all said was that they were so scared to get spotted by someone on their respective interview days.
I was advised by a GME friend of mine that you have to do a little research into the programs. When you apply to two programs that are very different (at the same institution) you should look at the phone numbers of the coordinator for each one. If they are different then they most likely will not know you've applied to another departtment within the same hospital. If they are the same, chances are the applications are routed through a GME coordinator and not a departmental coordinator. In that case they will know.
I did not interview for both at any one institution which made it less of a problem. However, I did have to explain myself to one ANE PD who asked if I'd applied to other specialties. Just do as I did and think of a good answer beforehand. Otherwise you will look like D%*K. My explanation left him with no doubt as to my ability to commit to either specialty.