Hi radek,
You can use the task "Actionlist" for this. It can enable/disable an actionlist, in this case the "Buttons" list.
Be careful when using the API though, you will need to change the core-prefix to be unique for every device, or else the feedback commands can be interpreted as normal commands...
I would use the first B-Station to send UDP or OSC to the second B-Station, and use that to enable/disable the list.
Greetings,
Bootsy