Panasonic KX-TD500 System Reference Manual page 246

2.11 Multiple GCO Assignment
Description
Programming
More than one GCO button of the same trunk group can be assigned to a
PITS extension.
(Example)
Assuming that Trunk Group 01 consists of the following CO lines.
TG01
Case 1.
Ext.100
Case 2.
Ext.100
System Programming
"Extension-Station (2/4,3/4)",
Type and Number
3-D-28
CO line 10101
CO line 10102
CO line 10103
CO line 10104
GCO-01
Ext.101
GCO-01
GCO-01
GCO-01
Ext.101
Reference
VT Dumb
10-G-1.02 11-C-26.00
10-G-1.03
GCO-01
GCO-01
GCO-01
GCO-01