Single user customization point for multiple build tools

I’m using Catch2 that I have cloned into a local Git repository. I am testing with multiple compilers, so I have multiple binary directories and so multiple cache files. I’d like to specify the Catch2 location in one place, rather than set it on the command line for each compiler I configure. I’ve done this so far by using presets. The end user (me) has to supply a JSON file in the preset format that specifies the location of Catch2 as a cache variable. This seems like too much boilerplate to supply a single value. Is there a simpler way to supply a variable value to all the binary directories?