Abstract: To distinguish multiple operator services systems (OSS) and provide services within a single local area telephone network, originating end telephone offices include database tables that correlate end user telephone numbers to selected OSS providers. When an OSS-type call is placed to an originating end office (OEO), the OEO uses the database to correlate the calling party's number to a code corresponding to the OSS provider. In one embodiment, this code is used to populate at least part of the ISUP called party number digit field of the SS7 signaling protocol. This number, as well as the original called party number are transmitted to the switching network which relies on the called party number digits field to route the call to the appropriate OSS.