You can setup templates within the Custom Properties, but you cannot apply the same rules/constraints that you can within the data card. I have found this to be a real limitation in the software. For example, I have a table on the drawing that houses revision information. The table is populated by custom properties which are pushed to the file from the data card. The user is only given edit capabilities within EPDM to modify the values of one field of this table. However, the user can edit any of the custom properties within the file. In my opinion, this is unacceptable.
Not to mention that I have found a couple scenarios in which you can the data card values and custom property values to get out of sync. The is a major issue for us.
This is a case where the API is your friend. The only way to do this is writing your own custom property manager. The Solidworks one does not interact at all with Enterprise.
Using the Property Tab builder you can mimick the datacard pretty well but it will not really be in sync. You can create a drop down box for a particular property.