Add Multimaterial names to the naming Customizer

[spingys]

Please add a node in the File name Customizer to add the name of a selected Multimaterial to the name. I'm going to have to output more than 4000 files in a future project where the Multimaterial needs to tie in with a specific environment and I need both to be in the file name.
I tried adding a new Studio for each color output and export it with the configurator, but unfortunately that doesn't tie the variables together...