[asterisk-users] misc newbie VoIP questions

[Rogelio]

asterisk-users at lists.digium.com

Please excuse the ignorance of these questions.  (I still have yet to
install and configure a VoIP solution.)  Depending on the feasibility
of some of these questions, I was going to try my hand at installing
something...

--Is there a way to pick the best SIP service for each country?  So,
let's say I buy service from several companies, and one country is 50c
per minute and another service offers 45c, how do the VoIP servers
(Asterisk, Trixbox, FreePBX, etc) auto switch between the best rest
rate?

--Can people's VoIP phones be a part of several extensions (on
different VoIP solutions)?

--Say about 10-20 of us want a virtual receptionist, and want to
rotate them so that calls work in different times zones (autoswitch on
certain times, auto go to a different receptionist if one is busy,
etc).  Where might I look to think about this?

--Google Voice will not forward texts and calls to foreign numbers, so
what type of solution would I need to accept calls (to a US number)
and then forward the texts / calls to foreign cell phones?

--Can DID number I buy intelligently forward faxes to one number and
all other calls to another number?

Thanks for any advice you might have.  I'm very new to all of this...