User Management for Project Manager allows the delegation of Group Membership management to powered users depending on an advanced configuration.
To benefit from this feature, just follow these 2 steps :
As JIRA Administrator, you can grant any users the Group Delegation Management since the features of Users and Group Management for Project Manager are driven by Custom Permissions.
As Granted User with the permission Manage Group Delegation, you will be allowed to define which groups will be delegated in which Projects.
As Powered User granted with a "Manage" Group Delegation, you will be allowed to manage :