Hi Dave Anderson,
At a generic level, this would require the following configuration in your instance:
1. Disable externally accessible groups (admin console >> system >> settings >> externally accessible groups)
2. Disable form based login (admin console >> people >> settings >> login settings)
However, can vary greatly depending on the type of SSO you are using in your instance. As such, if the above settings do not produce the results you are interested in, I would recommend submitting a case in your customer group ( MyJive Secret Support Group Administration FAQ ) as a next step, where a member of our support team can review through the specific configuration of your instance and provide a more targeted response.