Interesting concept. Basically a subset of clustering which is not easy to make robust in the general case….
There is a hook for a “pre boot” script to be run. You might be able to put something in there that expects heartbeats from the master. If it sees them then it keeps waiting. When heartbeats fail the the script terminates allowing the “boot” process to occur.
On the master side, spawning a daemon in the post boot script could generate heartbeats.
Lots of details to nail down to make it robust. But it might be possible.