public function loadRoleAssignmentForUserGroup($groupPath, $roleId, Request $request)
    {
        $groupLocationParts = explode('/', $groupPath);
        $groupLocation = $this->locationService->loadLocation(array_pop($groupLocationParts));
        $userGroup = $this->userService->loadUserGroup($groupLocation->contentId);

        $roleAssignments = $this->roleService->getRoleAssignmentsForUserGroup($userGroup);
        foreach ($roleAssignments as $roleAssignment) {
            if ($roleAssignment->getRole()->id == $roleId) {
                return new Values\RestUserGroupRoleAssignment($roleAssignment, $groupPath);
            }
        }

        throw new Exceptions\NotFoundException("Role assignment not found: '{$request->getPathInfo()}'.");
    }