Not aware of out of the box function but I'm wondering if the "invert-regex" option is for this kind of use case, unfortunately no sample both in admin the doc: Create a Service Monitor or the config samples: NSX-v 6.4 - Load Balancing capabilities + configuration examples (and more...)
I'm also thinking if creating a regex with inverse match of "Maintenance" for the service monitor would workBayu Wibowo | vExpert NSX, VCIX6-DCV/NV, Cisco Champion, AWS-SAA
Author of VMware NSX Cookbook http://bit.ly/NSXCookbook
https://nz.linkedin.com/in/bayupw | twitter @bayupw
I was thinking to create an Application Rule checking the body of the GET and based on that selecting "crafted pools" with only one node, but I didn't find a way to do a http get within a ACL.