The better way to do this is to create a ICDG with the ext in the group. Use the real ext for one staff, and use the ICDG extension for the second staff. Then you program a ICDG button on the phone to show incoming calls. You can even assign a distinctive ring tone for the ICDG button. If you want mailbox for the second staff, you create a ICDG mailbox and assign a message waiting button on the phone to show new messages.