2 Subchains in Fairlight 17? DyNamics Listen specific bus?

Are the "Send" and "Listen" buttons in DyNamics page of an audio channel (Fairlight>Mixer>Dynamics) hardcoded to a specific bus with a name "Sidechain"?

I have a scenario:
I have 2 buses (polish and english) and 2 sidebuses (for polish and for english version of the movie)
I have 2 voiceover tracks (Polish and English) Voice EN and Voice PL
I have 2 music tracks (for polish version and for english version) Music EN and Music PL

I want to use polish voicover as a source for polish music ducking...
...and want to use english voiceover to duck english music

I do not know how to make Dynamics on a specific track to listen to specific sidebus only?

When I press "Send" on Dynamics page it seems to create a new bus with a name "Sidechain" and the ducking is using this bus to listen to when I press "Listen" on a dynamics panel of a listening track.

I was trying to change "Input" of a listening channel using "Patch Input" window. Without success.
The "Send" and "Listen" buttons seem to be hardcoded to a bus with a name "Sidechain" despite the whole FlexiBus story. Am I right?

I was trying to add new subchains with name "Sub PL" and "Sub EN" and was trying to enable "Bus sends" in the sending channels to this bus but I could not make the receiving (listening) tracks to listen to this particular bus.

I was trying the reverse - to enable the "Sub PL" etc in the "Bus Sends" of the receiving channel. No success.

Is there any relation between the "Bus sends" in the channel settings in the mixer and "Send" button in the DyNamics page? The name suggests so but I am beginning to doubt this.

Are the "Send" and "Listen" buttons in DyNamics page of an audio channel (Fairlight>Mixer>Dynamics) hardcoded to a specific bus with a name "Sidechain"?

That is my understanding too, I can not see that this has been changed in the new Flexbus or if it has its hidden away.

I want to use polish voicover as a source for polish music ducking...
...and want to use english voiceover to duck english music

The way I would do this is to have both English and Polish setup in the same timeline and just mute and unmute each set when rendering. This way both can use the sidechain send and listen when needed. Its not ideal though as it would tack 2 renders.

Other DAW software do this by activating (hidden) sidechain send buses to each plugin or channels that have a send turned on.

On the receiving compressor, gate etcetera, when you click the listen option, there is a dropdown list showing any sidechain sends with a description naming what they are.

So in you case damago1, all you would have to do is select English voice track and press send. On the English music track, Press listen and choose "listen from English voice send". Then by doing the same for both English and Polish audio tracks, it would work together in the same timeline and would export out as different audio channels at the same time when rendering to different outputs channels.

I am sure Blackmagic should be able to introduce this now they have got Flexbus.