[Observium] Best practice for "Port Down"?

I quite like the idea that Observium notes "down" ports; however, in my case, most are false-positive in that they belong to users who power down after hours.

Our normal port description for an unallocated port is "NXC" (No Xross Connect) to the "Ignore Ports by ifName/ifDescr" and that has helped.

In a perfect world, I want to monitor all ports which interconnect between our switches, and all ports in the Data Center; but ignore everything else.

Can I put a negated RegExp in "Ignore ports by ifAlias Regular Expression" instead?

Thank you.