You can give users different access levels by creating multiple portals. One for each type of user.
If you are trying to allow people to see/edit only certain fields, you will need to create a separate portal for each team based on their privileges. In miniExtensions, you can create multiple copies of your portal. Each portal would have its own separate settings. (you can still combine them under one Page Header).
You can also create a different Grid for each group of people.