It is simple.
Do not modify the FBs (!).
I assume that each call of FB24 has an individual instance DB assigned to it. In your screenshot you have DB100, I assume that it is a different DB for the next scale and so forth.
These IDBs takes care of handling each instance.
Instead of one bit for all scales (M12.0) use individual bits for each scale, for example M12.0, M12.1, M12.2, etc.
For each instance of FB24, use the individual bits on the leg "SET 0".
Link each of the bits M12.0, M12.1 .. to individual buttons on your HMI, and you are done.