STARnet Digital has been enhanced by the QuadNet2 folks who refer to it as Smart Groups.  They have an excellent discussion on callsign routing at their FAQ

Part 1 – Introduction to ircDDB,
ircDDBGateway, and pcrepeatercontroller.

Part 2 – Introduction Continued
and STARnet Digital (Minute  4:15)

Part 3 – STARnet Digital Continued

Part 4 – STARnet Digital Continued and
Converting an Analog Repeater (Minute 4:50)

If you are looking to convert an analog repeater see the UDRC Wiki and you can obtain a UDRC II at NW Digital Radio.