Zenoss with Mikrotik Hotspots

I'm running Zenoss 4.2 and I've got a network with Mikrotik routerboards. I've installed the Mikrotik Zenpack, but I'm having trouble graphing the active hotspot logins.

There is a Cisco OID (1.3.6.1.4.1.9.9.150.1.1.1.0) that returns the amount of active hotspot logins along with the amount of active PPP connections. As my network works with several PPP connections the results of this OID are polluted.
I've found several OIDs that show information about active logins (1.3.6.1.4.1.14988.1.1.5.1.1.x), but non that show the amount. Is there a way I can generate a data source by counting the results from an snmpwalk