I found a solution myself.
Rationale: My plan is to use this functionality i.c.w. the encoder of the STEM module to adjust frequencies: consecutive presses of the encoder should select the frequency digit and turning it should adjust the frequency. That way I could tune the radio with just one encoder.
For anyone that is interested in the solution, I created an example where consecutive presses of Button 43 cycle through 3 different modes which create three different outputs of Button 48:
Step 1: Button 43 toggles through Virtual Buttons 100-102 with this Boolean function:
Step 2: The virtual Buttons 100-102 are now linked to a Modal Switch with three positions:
Step 3: And finally Button 48 uses that Modal switch to adress 3 different Logical Buttons: