Update: On further reading it seems like you may have been looking for a per host option. If this is the case than, unfortunately, the
service_inter_check_delay_method is more of a global setting and doesnt have the host level granularity that you may be looking for, I'll keep this post around in case others find it useful for their installs.
Sadly the official documentation hasnt been ported over from Nagios 2, but you may try playing with the
service_inter_check_delay_method option in your Nagios config.
Old Docs: http://nagios.sourceforge.net/docs/2_0/checkscheduling.html
# SERVICE INTER-CHECK DELAY METHOD
# This is the method that Nagios should use when initially
# "spreading out" service checks when it starts monitoring. The
# default is to use smart delay calculation, which will try to
# space all service checks out evenly to minimize CPU load.
# Using the dumb setting will cause all checks to be scheduled
# at the same time (with no delay between them)! This is not a
# good thing for production, but is useful when testing the
# parallelization functionality.
# n = None - don't use any delay between checks
# d = Use a "dumb" delay of 1 second between checks
# s = Use "smart" inter-check delay calculation
# x.xx = Use an inter-check delay of x.xx seconds
So instead of the default 'smart' method try something like
Note: the default smart check method works very well, if you choose to use a static x delay check, be sure to do a LOT of testing to make sure this doesnt flood your network in unusual and interesting ways... ;-)