John,
I re-read your post and I had mis-read it the first time... Without messing with "scheduled tasks" field on the client, it is not easy to skip security scans.
You can create a new agent for these systems and in the Patch and Compliance section you can change how often the system is scanned and also set a time frame in which they occur
What is it you are wanting to accomplish by skipping the scan? Depending on why, there are some ways to work around it, such as to set the scan to only happen only every x number of days, etc.