MedSTAR use similar callsigns to SAAS. There is MedSTAR 71 and MedSTAR 81. I've also heard MedSTAR 143, meaning they start at 1400 and I believe the 3 means they are the 3rd retrieval team (on call).
As far as I am aware, there are 2 teams on base with 1 on call. I've heard they have at least 3 retrievals a day.