good news: YES, it is!
in fact, when a host is detected as "DOWN", the notifications for its services won't be sent until the host returns to UP.
Which means: you don't have to define any dependancies in your cast! isn't that a great news ?
Note: it might not be clear; so don't try to understand if you don't care
BUT, you should know something: Nagios has a "weird" (but logical) mechanic when this happens: (in v1.2 to 2.10, and probably in v3.0-haven't tested it yet):
When a service goes down, nagios does a host check for its host. If it is found DOWN, nagios will send a HOST DOWN notification and no service DOWN notification. Up until now, everything is fine.
But then, in order to lighten the load, Nagios will not do any more host checks! it will simply test the services. As long as no services are up, it will keep on sending HOST DOWN notifications...
Which means that, if your host goes UP BUT your services do not, it will keep on sending HOST DOWN notifications, even if the host is UP ....
We have often the case when we have only 1 or 2 services on a host...
that's a bit of a problem, so, in the end, we try to avoid this mechanic just because of that