In Indiana, can a volunteer firefighter display a red led facing the rear of the car?

I am looking at hooking up my forward facing blue lights, but wanted to have something facing the rear as well, and wasn't sure if there was anything specific that I could or couldn't do. Tried looking up the laws, but it didn't say anything about a rear facing red/blue light combo. Not wanting to do it without knowing and then get fined for impersonating a police officer or something crazy like that.