I asked for my therapists and my doctor to work together right from the beginning. My therapists don't share details of any of my traumas, just general comments about my overall functioning. When they talk, it's like a 1-2 minute phone call most of the time.
I can't imagine not having them communicate. Otherwise, they could waste my time and money working at cross-purposes. Working together, they were able to priorities my needs. Which, interestingly enough, was a very different list than what I *thought* my priorities would be. Thank goodness they knew what they were doing.