Create snapshot of all servers in ressource pool with tag xyz

Hi,

i am using the workflow: Create snapshots of all virtual machines in a ressource pool.

now i want to check in that workflow if a virtual machine has the tag xyz. if so, then do a snapshot. if not, do no snapshot. i think the best way is to get all vms with this tag in initialize part of that workflow in variable "allVMs", but how can i achive this? Or does anyone have an better idea?

regards,

bkgc