Reviewing through your description, you should be able to assign content to more than one category in your instance (Managing Content Categories ). For example:
However, if you are wanting to place multiple category widgets on a specific page which pull from different places in your instance this is not an option in the OOTB product. That being said, if you are interested in customizing your instance to include this feature our Professional Service's team can assist in determining the scope of the project and work with you to develop a custom solution which meets your use case. If you are interested in this option please submit a case in your secret customer group here in the Jive Community and the next available support engineer can get an engagement set up for you.