Use /g+ to add a user or another group to an existing group.
Required Permissions
To use the /g+ command, you must be a member of the Team Foundation Administrators security group. For more information, see Team Foundation Server Permissions.
TFSSecurity /g+ groupIdentity memberIdentity /server:servername
groupIdentity
Specifies the group identity. For more information on valid identity specifiers, see TFSSecurity Identity and Output Specifiers.
memberIdentity
Specifies the member identity. For more information on valid identity specifiers, see TFSSecurity Identity and Output Specifiers.
/server :servername
Required. Specifies the name of the application tier server.
Run this command on the local application tier computer.
You can also add users and groups to an existing group using Team Explorer. For more information, see How to: Add Users to a Server-Level Group.
The following example adds the user "ajesper" to the "Team Foundation Administrators" global group.
>TFSSecurity /g+ "Team Foundation Administrators" n:ajesper /server:MyAtServer