I have Optimum Voice as home phone line. I have an AT&T office phone line coming into my home. I have a 2-line phone and want to hook up both lines. This I have done, but now I want the home line (Optimum) to go into an additional phone (single-line) and I can't seem to get the optimum line working wth the addtiona single line phone. Can you split an optimum line from the modum into 2 lines for 2 separte phones? Have I made any sense here? Thank you.