My suggestion is to change trunk’s
For example 10 analog line’s
Line 1,2,3 …..10
Set trunk 1-1 for line 10, 1-2 for line 9 …… 1-10 for line 1
D3 in sel set to 2 or 3
Now your user will be taken lines from line 10 to 1
Your local telecom should be set this same method to select line but from line 1 to 10 (always start from line 1)