IBM RTC 6.0.3: ccm How make Read only attribute for a team members only

There are 2 pre-condition for Save Work Item whose name begins with "Read only"  Read only Attributes for Type and State, Read only Attributes for Condition.    To limit behavior to a Team area would require the behavior be added under the "Team Configuration / Operation Behavior" for the Save Work Item probably on the "Everyone" role.    

To use the 2nd you'll have to devise Conditions under Work Items / Attribute Customization, but your end goal may not lend itself to the 2 kinds of pre-conditions here.

For details, see Setting preconditions and follow-up actions and Operation preconditions and follow-up actions.