Agent Requirements - Idle CPU?

Hi,

We have a few machines that we'd like to perform builds, but they're sometimes used for other things (Release Builds, Testing etc.)
Is there any way that TeamCity can run a config on an agent only if it's CPU usage is below a certain percentage?

This will also allow team members to offer up their own development machines as agents, and them only be used for TeamCity builds if they're idle.

Thanks,