I need some IP configuration.... I developed some software that works in our business of 4 location and one web site. Each location have static IP's, and with 4 ISPs. I have a problem with one location, a partial T1 line. The internatl network and going IN and OUT of the internet is fine, the problem is with the software trying to connect to it's own loaction, ie:

Loc A IP 111
Loc B IP 222
Loc C IP 333
Loc D IP 444

let's say I can be at Loc A with IP 111, I use the software to connect to all other locations and Loc A as well, BUT... when I use Loc D, I can connect to all other Loc BUT Loc D.

I don't know if in my IP scheme should I be using the the static Gateway or any of the DNS I received on my IP's DNS or should I still use my DNS as my local router 10.0.0.1 IP

Does anyone follow?? Any recomendation??