Simult. Add-Monitor and a Thunderbolt Drive

I want to use an imac as a second screen for macbookpro....Since i'm running big pro tools sessions, i want to use a thunderbolt drive (which only my macbook pro will take)...The problem is, the thunderbolt drive and the external monitors need to be plugged into the same port.... any suggestions on using both an ex.display and the thunderbolt drive? thanks!