Dialog with RFC adapter possible?

Dear experts,

We need to connect two SAP systems and have the requirement to use SAP PI for this:

SAP ERP A <--- RFC adapter ---> SAP PI <--- RFC adapter ---> SAP ERP B

In the target system, there are existing RFC-enabled function modules (custom developments) which prompt (dynpro screen) dialogs to the user.

Is it possible to call these RFC functions with dialogs via PI (like it is possible when using TRUSTED RFC connection directly between SAP systems)?

Thanks for your help!

Kind regards

Pete