facebook friends are really groups

I think facebook 'friends' are unclearly defined.
There are many types of friends.

- family members
- business contacts
- one time contacts (e.g. if you want to view baby pictures of a coworker)
- people you went to school with
- people you went to college with
- people that live in your street
- people that share your hobby
- people you tell your secrets to

I think there should be an EXTENSIVE extensive amount of GROUPS, that people may join or not. These groups can be created by members as they are needed.
Also there should be extensive SUBGROUPS. this is not clearly available now on facebook.
'friendship' is than defined as common group members
so there should be a group for every
country, city, street, year of living there
but also for every
country,city,school, year of attendance