Calls stack up on 1 line key with incoming calls


How would i go about setting up FreePBX to send calls to multiple line keys on my cisco ip 7970g phone with the same extension # on all of the line keys.

example… i am on a call that i took from user a. User b then calls me on the same phone but is showing up on the same line key. (i want that second call to show up on line key 2)

This site is what I used to configure my phones.