have R12 system w and a station, type 6424, number 4170. This is a Help desk phone. By day this extension forwarded to technician#1 ( to his mobil phone), at night to technician#2 ( mobil) next day to #3 etc...The technician group about 5-6 people. I like to admin 5 button with light indication what show the 4170 extension forwarded who's mobil phone. ( sorry for the grammar) How can I do it?