Tom,

Yes, you can file "Joint" Federal Returns ans separate State Returns.

Agrred that you can file jointly on your federal tax return.

Agreed that you can probably file separately on your Indiana return. However, you can also file JOINTLY on the Indiana return, and you should prepare the Indiana return BOTH ways to determine which is the best course of action tax-wise.

You CANNOT file EITHER jointly or separately on the Florida return, since Florida has NO state income tax and thus has NO return to file.