The group slug is generated from the group title. Your question is unclear – do you want to be able to manually set the group slug to something different?
yes,manually set the group slug to something different
no, I want to make the single group by fill in not generated from the group title
Ok, you can use bpdev-groups-extra ( http://bp-dev.org )
add a text field as described in the sample file and then apply a filter on the slug,
i’m not sure it will work.. i will try and update you
and do you think it works on the bp-event?