Automatic shutdown of non critical VMs

Hi,

I would like to know if it is possible to automatically shutdown non critical VMs in case of an ESX server failure.

We are runing about 25 VMs in our 3 ESX server cluster. Some VMs are critical (AD, Exchange, ...) and some are non critical (Virtual appliances for software deployment, OS deployment, Lab VMs, Test servers, ...)

If one of our ESX server goes down because of a hardware failure, we will not have enouth memory to all VMs with only two physical servers. So I would like to know if it is possible to automatically shut down non critical VMs to have enouth memory to run critical VMs.

Thanks in advance,