Socialengine url重写为组/ id更改

Question

I want to show the group name in the URL and not the id so instead of :

site.com/group/1
to show
site.com/group/mygriupname

I`m looking at the manifest.php file for groups at this line

'route' => 'mission/:id/*',

I dont know what variable holds the group name instead of id I replaced group with mission.