Those intercom systems are for person to person on the same vehicle or if you were say in a rally car.
If you want vehicle to vehicle communications you get into using radios and PTT setups that can be installed in your helmet. Rugged radios is great stuff a couple of other crapcan teams use them without issue. In the end they are baofeng uv-85 radios that are painted blue and helmet kits.
We started using the midland radio kits with the motorcycle setups but found the midland radios to be way too quiet and the harness was way too fragile. I would at least go Motorola if you want to go this route. Also Midland radios are not easily compatible with better Nascar or IMSA style harnesses that are made out there due to the odd way they do things.
Our crapcan team uses baofeng radios from Amazon, a nerdie racing harness that has PTT on the steering wheel. And each of our drivers then has a nascar style helmet kit which can hook into it. The downside of the baofengs is they aren't as easy to setup as you can't just punch in the 01-01 like you would on a Motorola setup and technically they are illegal to use in some bands if you don't have a license as the radios are more powerful then the family band ones.