Appending the dialed digits in ARS 1

[SWDMVP]

Strange one, but I thought someone here might know the way to get this done.
With SIP, the carrier can be anywhere. Well, we have one in Canada. The issue with that is that the user wants to dial a toll free number.
very infrequently, some toll free numbers are only valid from inside the USA, not Canada... Our SIP Service provider told us to have them dial a prefix of 7 numbers, then it will work. I can dial this xxxxxxx then the toll free number of 800-920-7487 and it works.
The question is how can I add this to ARS, but ONLY to that 1 toll free number and not mess up any other calls?
Thanks for any help on this.

 

[TouchToneTommy]

Assuming that you dial 9 and the number for outgoing calls, and you prefix 1 in front of the area code and telephone number

The special prefix is 1234567


System Short Code 9N / Dial / N / ARS


In the ARS table

Code: 18009207487
Telephone Number: 1234567N
Feature: Dial 3K1
Line Group ID: the SIP URI Line Group for outgoing

 

[SWDMVP]

Well, that worked!
Thanks. I had it backwards.