Alert for a UnDP

Hi,

Please help.

I need to create an alert for UnDP, where Value from UnDP greater then Value from another UnDP.

For example UnDP iemStatusProbeCurrentTemp Value greater then iemConfigProbeMaxTempThreshold Value

This is APC UPS OID's where iemStatusProbeCurrentTemp show a current temp, and iemConfigProbeMaxTempThreshold show a treshold value.