We used to have one physician in-house to cover both OR and L&D, with second call at home as backup. Now, both are in-house, with first call (comes in at 7pm) still taking most of the calls from both OR and L&D, but second (had been working all day) being able to handle one of those locations immediately, if first is engaged. When we first made that change, I brought up the idea of formally splitting the two, with one only covering the OR and the other L&D, but that was not popular.