I have to admit that I don't know anything yet about performance issues and how parameters and multi-select filters play a part in it, but I had a play with parameters and combination values and can make something work. Looking at the logs, I think the resulting query looks totally ugly though so I've no idea if it will help with performance.
I've done an example for a numeric field and one for a string field.
Does that help?
MultiSelect Parameter.zip 1,013.6 KB
Actions would be a better alternative. Less work, less clutter, and better performance.
I've learned two things from that. 1, that you can have multiple values in a Parameter option (e.g. "6","32"), and two, that the "CONTAINS" syntax is useful here.
Thanks for the suggestion. Are you able to point me to a good working example of this, or build a small demo? (maybe from Dana's workbook above?)