I assume you want the button Click to determine where the incoming BlueTooth data should be posted when it arrives.
One way to do this would be to use a global variable with the component block for the desired target label,
and have the button Click event switch the global to point to the appropriate Label.
When the data arrives, use the global variable contents and the set Any Label.Text block to
display the new data.
Since I don't have BlueTooth in my PC Emulator nor a car in my living room,
(you're still working on that OBDII app, right?)
here's a sample app using a repeating Clock to deliver incoming data.
After each button is pressed, its associated Label received new time signals.
ABG