What if the set of wires from Phone 1 are a different color from Phone 2? Also, if I need to install a DSL filter inside the house, where would I install it?

Can you explain a little better?

Is Phone 1 and Phone 2, Line 1 and Line 2, Jack 1 and Jack 2 or really two different phones like the shoe phone and the Mickey Mouse phone. How many phone devices do you have in the house?

You can get a single DSL splitter that installs in the NID or inside or you'll have to put filters on everything but the modem. An answering machine and a telephone in the same room can count as 1 filter needed. There is a maximum limit of 5 filters