It sounds like that you want to create additional sroutes to different locations and also add a prefix to the calls that go to those locations. If this unit is the older A400, then you can create the sroute, but you cannot create a different prefix for each route. In the old A400’s you can only create one system wide prefix. This is done in the config->iptg area with outgoingprefix. If you enter a prefix here, then all calls that originate from this Tenor and go over IP will have the same prefix added. Additionally, if you use sroutes, you will need to set the dn in the sroute to private because adding a prefix in the iptg changes the number from public to private.
If you have the ax or as 400, then it is possible to have a different prefix for each sroute by creating a new ipdialplan for each.
Hope this helps.