Cisco ATM Virtual Interface Monitoring

Is there a plug-in or documented process that allows Nagios to gather the 5min input and output rates for an ATM PVC interface? My research has shown that you can’t link to a traditional SNMP OID value using check_snmp. The ATM virtual interface appears to require a few calculations to gather the correct value.

My end goal is to monitor all my MPLS router interfaces for utiliziation and graph accordingly.

Thanks!