Examples for Group Entity
In the Administration domain, you can get group details in a number of ways:
Getting Groups 
To get the Windchill Risk and Reliability groups, use the following GET URL:
URL
GET /WindchillRiskAndReliability12.0-REST/odata/Administration/Groups
Getting Specific Group 
To get a specific group’s details in Windchill Risk and Reliability, use the following GET URL:
URL
GET /WindchillRiskAndReliability12.0-REST/odata/Administration/Groups(<groupID>)
Getting Users in a Group 
To get the users for a group in Windchill Risk and Reliability, use the following GET URL:
URL
GET /WindchillRiskAndReliability12.0-REST/odata/Administration/Groups(<groupID>)/Users