Ways to Restrict Access to sections of a CRM Data Base to specific group of Users

Our Company is planning to add International Partners soon. How can we limit access to CRM database records to Partner Users? (i.e. They should only be able to see Leads, Accounts, Contacts, Opportunities, Activities etc. pertaining to their sphere onf influence).

First thought was to create System Views that limit the scope of the records. But how can I restrict their access to only these system views? Can I assign views to Teams ?  If so, how ?