You can legally carry as many as you want. Carry all of them at once, if your pants will hold up all the holsters. You can carry them taped to your forehead if you want. You can carry them loaded or unloaded. The only thing that Indiana statutes define are the locations where you can't carry (such as schools).
I can envision some Dr. Seuss rhyming coming from this post...
There was a carry poem on here somewhere!
I can't find it, but it was very Dr. Seussish. "You can carry in your car, you can carry in a bar."