Hey, fellow Hoosier! Yes, you can do this and the easiest way is to do it with an Invacom QPH-031 from one of the sponsors. This LNBf has both circular and linear polarization on the same unit with seperate cable outputs for each type. Two outputs for linear and two for circular. I like this solution because you don't have to mess with multiple LNBf units, offsets, etc. Hook up one cable from your dish box to one of the circular ports and hook up another cable from your fta box to the motor and then to the linear port. Simple as that.
Other way which may be a little cheaper is to use a multiLNB holder. This should allow you to use your existing circular LNBfs for your Dish subscription and pick up a cheap linear LNB for FTA use.
Here's the link to Sadoun's page:
QPH-031
I use one of these for my 1.2 meter dish and it works great. Hard to beat the Invacom.