You are licensed... as I am... to use FCC Part 95 radios for GMRS only. We are Not "Allowed" to use a FCC Part 90 radios for HAM.... Nor is a licensed HAM user allowed to use a Part 90 HAM Radio with GMRS frequencies. This is just the Law according to the FCC.
100% truth. The way it is written is stupid. To follow the rules you would need multiple radios and licenses to use the different services. Depending on who you talk to race radios are already in a grey area with commercially owned frequencies.
What I can tell you is that I only have two radios in my Jeep. CB and HAM. I have a GMRS license and a technicians license for HAM.
It is possible to use one radio to talk on race, GMRS, and HAM. It is not legal due to the way the rules are written. But it can be done if you wanted to save some space/$$$. At the end of the day as long as you have a license for the frequency you are using it is going to be hard for anyone to know what equipment you are running.