I believe I've just figured it out. The answer is the Joint Editor. Typically, in these setups there are two ghost bones: one "conformer" and one "operator". Selecting "Bend" from the drop-down menu in Joint Editor, I hit the "Affected Actors" button and set the operator to affect the conformer, and the conformer to affect the hip, effectively creating a movement chain.

It works, but it seems to be moving the entire hip, rather than just deforming a specific part. I think I'm on the right track.