When you say view the details and all three should be connected,I take it that the main location would simply need access to the database of locations B and C so it view data. Connecting to different databases is simple. You could add functionality to location A's software to access these other databases pretty easily by usng their IP address. A web service could do exactly the same thing, just store it where it makes the most sense (does location A have a web server running?)
As for your chat problem, I think we'll need some more information. You've tried it with both firewalls off?
Hope that helps,
hericles
Veteran Poster
1,065 posts since Nov 2007
Reputation Points: 156
Solved Threads: 228
Skill Endorsements: 9