BookwithMatrix might not get the rick done either. As some folks have noted, married segments can and do get in the way. I recently encountered this with trying to book a multi-leg trip to ANC and using BookWithMatrix. I had to use multi-site on AA and tinker with my how I entered cities in to get the connection I wanted. In your above intermarry for instance: ORD-DFW-MIA-TYS, try in multi-city, ORD-DFW and then DFW-TYS or ORD-MIA-TYS to see if you can pick up the legs. Not guaranteed but you may then be able to get at the leg you want to get at. Hope it helps.

Safe Travels