You define the maintenance schedule in a policy. So you have to apply this policy to the VM's with the EPO Agent installed.
What would be a possibility is to create an custom group which contains all the EPO agents and apply the policy with the maintenance schedule configured to it.
The policy could be a child item of your monitoring policy and inherits all monitoring configuration from it. The only override is the maintenance schedule. This makes sure you only have to configure your monitoring threshold in one policy.
