Hi @jbielecki, I don’t think that kind of option is available. I have in the past used the software in which radiation was calculated as you mentioned by defining reflectivity and emissivity to faces and doing a pre-calculation of exchange between the faces. Unfortunately, I can imagine a viable workaround, however, you are welcome to add this requirement to our vote for features section detailing your use case and how you imagine it working.
Of course, if anyone else has an alternative please correct me.
Sorry, I cant be of more use,