Excluding some VMs from alerts?

I have an alert set to send an email when a VM storage utilization is at 99%. I want to exclude some VMs from this alert but can't seem to figure it out. I want to exclude VMs that start with MMWS and MNWS. I tried using the "does not start with" and "does not contain" but I still get alerts for VMs that start with MMWS and MNWS.

Please Advise.