Operating a hot-spare block producer with P2P enabled

I’d like to operate a hot spare block producer when the block producers both have P2P enabled. Before P2P you would manipulate firewall rules to prevent the hot spare from propogating blocks, whereas with P2P, you start the hot spare with the following flag:


Has anyone got a script which will monitor the main block producer and SIGHUP the hot spare if the main bp goes down?