Newbie can't populate value list based on value of field

[dontodd]

I'm trying to populate a drop-down list with one field based on the value of another field (both fields contained in the same table).

I have a table, contacts, containing:

contactID

isFacilitator

The isFacilitator is a yes/no dropdown box for data entry.

In another table, I need to enter facilitator information. I'd like to populate a drop-down value list there with the contactID of all the records where isFacilitator equals yes.

This seems like it should be pretty easy, but my googling and searching here doesn't seem to help me much. I'm a total noob to FMP, which probably explains why what I'm finding seems far too complicated.

What's the basic approach I should take to this?

TIA!