I must have expressed myself wrongly.
I know how it is done and why (for OM2ZZ)
In Radiozurnaly, the connection from the NF transformer is described, if I remember correctly, and the separation of the control signals is solved there.(for Hlavac)
Because I don't have one at home and I can get it from a store, I only have one and he won't send it to me because the order is under 500,- SKK. I changed my mind to solve the NF department by optopath. Unfortunately, no radio amateur did it. But luckily, people are into audio engineering. And I've already found two solutions, I'll just try it and hope that it won't cause me a big distortion (Ktore dost vadi Furierovym Transformaciam)