In-car Intercom Search

I teach High Performance Driving (HDP) for a local car club. Part of the instruction process involves taking students out for rides in the instructor's car. This allows the instructor to teach from the driver's seat - demonstrating how to drive a certain line, how to take a certain corner, etc. It's also helpful for beginning students to get a sense of how they will be able to drive if they continue coming to events and learning.

An intercom system is essential when instructing. When hopping from student car to student car the only viable alternative is a motorcycle intercom. I hate them - I've tried a couple and the wires always break, the volume control stops working, the microphones fail, etc. But for the moment I don't see a viable alternative.

For the Type65 car, I really want to install an in-dash rally-car style intercom. Since multiple people will be in the pax seat I need a microphone/ear-piece component similar to a motorcycle intercom that can be easily slid into and out of a helmet. PTT controls are OK, but I'd prefer voice-activated mics (again, like found in a motorcycle intercom). What I don't want is thin wires that break easily, or cheap electronics that fail regularly.

So far I've not found something that does not require permanent helmet mounting. If anybody knows of a system more suited to the needs I've outlined, please contact me.