Call to a group of phones

Hello all,

i am looking for a particular feature, that could be part of SIP, but i can’t find any help on the net:

I need to receive a call to a group of phones, all mine(same userid) but in different places (office, home), and then pick up one only.
Do SIP protocol offer this feature as default ? In this case i should be able to register with more than one phone and same userid in a “registrar”, but it don’t seems to work.

Then, about Asterisk, maybe same thing could be reached using different extensions(userid), making a call to a group. Does the pbx allow this kind of grouping for calls ?