Hello robinlb1900 and idjacobs,
Studio One doesn't support Surround at the moment - but there are workarounds inside the DAW which allow Surround Routing (mono/stereo track bussing).
Unfortunately I don't know how to set this up as easy as possible in Studio One so I recommend to get in touch with Presonus itself in this case to get the best solution for you.
Please make sure you insert the Surround-VST version of Synchron Pianos in Studio One before you start the routing process.
Since Surround Routing is handled differently from DAW to DAW, there are no ready made solutions here - sorry to say.
If you have further questions, don't hesitate to ask or write a mail to:
Hope this helps!
Best regards,
Johannes