I know that mine do, they let me know openly, for example if I bring something up in therapy that relates to my meds he'll let my pdoc know so that when I have a session with her I won't forget to bring it up.

In my case the two work in the same office, for the same organization.

I know you sign privacy forms when you start, there may be something in there that specifically addresses this.

I don't know if all cases are the same. I would ask them, there is no harm and you have a right to know.