I would also say that some would depend on each of the T's theoretical orientations. some thories play nice together, some can parallel play and others are incompatible.

I use a "tratment team" approach with a T, a T who does body work and a Pdoc. I am the onlt overlap between all three as all are in private practice. While to my knowledge they have not spoken to eachother they all have signed releases so that they could... Just to avoid confusion and/or unintentional triangulation.