Copy and paste the main ARS, rename it "Remote" In all of the short codes, or the short code of you choosing, put ".SS" at the end of the telephone number. So if you have a code of "1N;" set the telephone number to be "1N.SS" with a feature of dial 3k1. Build a seperate dial out code, in system short codes, of 6N or 7N with the feature set to dial and set the line group to the newly built ARS line group you named forward. Now to use it, just tell the user to set the forward number with new dial out code and the number.
This example is in 4.0
For previous versions without ARS...
Just copy and rebuild all of your [9]system short codes to be [6] or whatever and add the ".SS" to the number.