Unified Messaging in a Forest with subdomains

[Joe L]

Hi,

We are looking at deploying Exchange 2010 (we are running Exchange 2007).
We have one forest with multiple subdomains for each physical site.
We use Alcatel PBXs at each site as our standard phone system and are
looking at options to use Unified Messaging using Microsoft Exchange 2010. Do
you know if we could support all our subdomains with (for example) only 1
Exchange 2010 Unified Messaging server role running in our main datacenter?
Or do we need one server running Exchange 2010's Unified Messaging (and also
hub transport role as apparently this is required) at each subdomain?

Cheers for any advice,

Joe

[Joe L]

Hi, does anyone know of a better newsgroup or source for this Unified
Messaging topic?
Looks like its not a typical question for Exchange design people

cheers,
Joe