Not sure what your the data you are using looks like, but it
soulds like in the fill method to your Data Management Service you
could pass the share name. Then when updates are made users will
only get data associated with their share. Does that help you?
Also, if you are using messaging and not the data management
service, you can control who gets what messages using selectors or
suptopics. See the developers guide for more info. Hope that