what you could do is:
change the host check command, so that, instead of doing a check_ping, the command does a check_nrpe
=> when nsc++ is running, it will answer its version and return a OK status
when it is not running, it won't answer, so you'll get a "connection refused by host" or something like that
(and when the host is down, it will do the same, so you won't miss any notification).
Hope this answers your question