GRP-15: Use a group for task assignments within an application

Executive Summary: 
A community member needs to assign a task in an application to a group (as opposed to an individual).
User Importance Summary: 
Community members need to be able to define arbitrary groups of people to which they can refer for authorization and communication purposes. Project teams are organized in groups, and project activities are often group activities. The ability to reflect a project's management structure in groups and use those groups for task assignments eliminates a nontrivial amount of clerical labor (and clerical errors).
Target Communities and Sizes: 
Community projects - 100 < N < 1,000 Team members of community projects - 1,000 < N < 10,000