[Asterisk-Users] Two Asterisk server

[Mimmus]

Hi,
I have two Asterisk server linked by a IAX2 trunk with two PRI+DID:
 Site1: XXX<100-499>
 Site2: YYY<100-499>
(I masked real number with XXX and YYY)

  PSTN PRI1 --- Asterisk1 ...IAX2... Asterisk2 --- PSTN PRI2

Users:
- keep their extension when moved between sites
- can be reached from PSTN with both XXX<ext> and YYY<ext>
In other words, dialplan is shared between servers.
Actually, we have two Alcatel PBX 4400 working in this way.

Can I do this with Asterisk?

Thanks
Mimmus