I would look at integrating NSClient++ with your nagios installation, take a look at these guides, some may be related to Nagios XI but they will work with Core:
http://assets.nagios.com/downloads/nagi ... _Agent.pdf
http://www.nsclient.org/nscp/wiki/doc/c ... tion/0.4.x
http://www.nsclient.org/nscp/wiki/doc/usage/nagios/nrpe