I have never tried it (therefore not an answer) but if you create a
Type=oneshot systemd service where ExecStart= points to a script that somehow probes your point to point connection and exits only when it's ready, and the service has RemainAfterExit=true, then the service will become active when mounting can be done, I think. Then in fstab you use x-systemd.after= and x-systemd.requires=. Not tested, I may get the details wrong; the idea itself seems promising though, investigate.