Thinking Sphinx w/ Bounding Box + Radius

On my website I allow users to search for things such as 'Columbus Ohio', 'Miami fl', etc which I then turn into coordinates using Yahoo Placemaker and then do a radius search using Thinking Sphinx. This works great for small areas but when the user searches for something like "Ohio" or something similar a lot of results are being excluded at it's getting the coordinates for the center of Ohio and doing a radius search from there.

It it possible to use Thinking Sphinx in combination w/ a Bounding box of coordinates a开发者_如何学Cnd a radius.

For example search everywhere inside of Ohio's geographic bounding box as well as 50 miles around the edge of that box?

I'm afraid Sphinx doesn't have that depth of functionality - the geo searching is only through a single point and a radius around that.