Hi Tom,
Another option could be to put the select into a repeat.
Instead of using a select multiple, you could use it as multiple select_one questions in the loop.
My example is recording the presence of multiple GNSS receivers, with their make and model number. instead of being able to select two manufacturers, you select one, then the subsequent model number, then add a new response to the repeat.
Not as clean as a choice_filter of course, but it seems to work for what we were after.
Regards,
Dan