Sikorsky had designed a system that might be offered if the S-67 had entered production. Basically, there were two modes: If flying independently, the system would blow off the rotors all at once, followed by canopy separation and ejection initiation. If flying in formation,a different mode was selected. A strong blade would rise up in the rotor hub at the 3 o'clock position which would have the result that each blade would be thrown forward. One all were gone, the ejection sequence would commence.
As a minor, somewhat irrelevant side note, a Tilt-Rotor, regardless of mode would just use a conventional ejection seat. Nothing special is required.