Wireless Track Light Switch
I am by no means an expert, but I don't think what you're looking for is something inherently compatible with the idea behind track lighting.

Track lighting is, fundamentally, a hot rail and a neutral rail separated by insulating materials.  When you install a "head", it contacts the rails and completes the circuit, so when you energize the circuit, you get current through the head, producing light.

The hypothetical wireless device you are describing would have to interrupt the rails somehow, turning off power downstream of them.  This would not divide your circuit into segments, however, it would just turn off everything past your device.  A multi-rail track would allow you to get around this, but would also solve the problem inherently by giving you multiple parallel track circuits.  Short of modifying an existing track to permit a third-party device to open and close the circuit, I'm not sure how this would be done, or if it has been done commercially.

An alternative is something that exists between the head and the light bulb (or integrated into the light bulb itself) that allows you to connect and disconnect the bulb from the circuit.  Smart-home-based lighting might be an easier (albeit potentially pricey) alternative, permitting you to group different lights together and issue them commands wirelessly.