Mark

With the later releases of the DSX (which you have) you can assign the same line to multiple groups

group 90 could be 1,2,3,4
group 91 could be 4,3,2,1
group 92 could be 3,4

In the Dsx each extension can use the group you assign.

I sometimes assign a specific line (not a group) to speed dials that are set up to turn off call forwarding like *72 from the CO

Old releases in the ones or early twos, a line could only be in 1 group.