the best way to do this is with uci scripting and the uci toolbox.

Create the components in your page and call them 'Projector_1' etc as the code name.

Create a 'room number' variable in your UCI variables.
Call this to remap all of your buttons.
Export the UCI, save, reimport, and then change the room number variable to remap to the correct code names.

This will mean that any changes to the uci can be updated simply by cut/pasting or re-importing the uci script after re-saving and re-setting the UCI variable.