symmetry boundary in flow model, symmetry plane not in flow domain

Hi there,

I'm buidling a model of a heat exchanger which is symmetric along the flow direction (heat transfer+laminar flow). Unfortunetly I got two pipes which aren't part of the symmetry plane but have the same distance from it.

Is there a way to take the computational advantages of the symmetry nevertheless? I only found the possibility to declare the symmetry boundary for the heat transfer, where the symmetry plane is inside the relevant domain. I would need something to mirror the pipe to the other side..

Thanks,
Björn