New phone system

Hello,

At my company we are in the process of constructing a new building. Our current phone system was put in by Lucent Technology. What we are finding is that since the take over it has become very expensive to keep this system. Our plan is to rip out the old system and let one of our local phone companies replace it. Once replaced we want to get a t1 line to run between the 2 buildings so we have one phone system. My question – we currently have DSL for our internet service if we have a new system with a t1 line running between the buildings can I hook those users up to my dsl account without adding another dsl account. If there are any phone experts that can add some input I would appreciate it.

Thanks