Do you want the multi select values to dynamically update based on what is in the table and not what is in the org?

This is possible with our normal drop down box filter - when your filter source is an aggregate model grouped on the picklist field.  This shows values actually in the data rather than what is provided from field metadata.   This does not work for multipicklist filters because we do not let you use a model as the source for the multipicklist filter.  We will consider this for a future release though.

My mind is blown right now.

If you’re not afraid of hacking the XML for the page, you can have the filter be multi picklist now.

Thanks, that’s helpful. A multi-select picklist would be even better though. If a model returns a list of accounts that span 12 different US states, I’d love the picklist to show only those 12 states and allow me to pick 3 or 4 of them.

That’s the part that needs clarification though. Is it that you want to dynamically update the list of states to what’s currently in the model? Hopefully not.

I believe that the options available are only generated on page load and not dynamically changes without a serious effort with code.

Best I would suggest is to do the same as Rob, except make sure that it represents only the states as they are loaded into the table on page load. So, add a condition on the aggregate model to only include records found the in model that represents the table.