Any way to find all my devices or groups that have Custom Thresholds?

Hi,

We want to audit our system and find all the groups, devices, etc that have custom thresholds to make sure they're all correct.  I tried to use the Custom Threshold report, but everything I try to do just gives me an error that says I can't check more than 50,000 things at one time.  I tried to point it at a folder that only has 300 devices in it, and even that wouldn't work.  This report is not a viable option if I have to run it 100+ times because I have to point it at groups that only have a few machines in it.

So, I'm hoping there's a way to do this via the Powershell Module or API or something.  Does anyone know how this can be done?  I thought maybe I could say give me all the groups where the CustomThreshold wasn't blank, but I can't find where the custom thresholds are stored.  If anyone knows how this can be done, let me know.

Thanks!