Well, a star topology refers to where cable has been run from. A Norstar, just like any other digital phone system requires 1 pair from the phone jack to the phone system.
Star topology just means that all your phone cables run directly to the phone system. That's not really necessary. In larger sites, horizontal cabling is used to feed to local IDF's (cabling closets). From there, the IDF (usually a 25pr. cable or larger, depending on the number of extensions it'll feed) connects pairs to the local phone cable runs.
If you're asking whether you can run 1 pair through your office, and tap into it wherever you need a digital phone, the answer is no. 1 pair - 1 phone.