Not in the UI itself. You can get this information out of the API and you could be alerted based on committed and overage values with a web service, but stopping someone from adding a user, no. Only way would be a web interface that calls the API to check usage before calling an API to create the user. My question would be why? If the licenses costs the same for the committed and overage, there should be no concern if you really need them.
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Robert Wakefield-Carl
ttec Digital
Sr. Director - Innovation Architects
Robert.WC@ttecdigital.comhttps://www.ttecDigital.comhttps://RobertWC.Blogspot.com------------------------------