While watching the episode of Sunday Night posted by billywhizz
https://au.news.yahoo.com/sunday-night/video/watch/28288354/the-claremont-killer-part-one/ one of the commonalities between the crimes were that the missing girls left alone. We know that SS, JR and CG left their group of friends and were alone.
The famous quote from the Rayney trial was
"Mr Rayney’s lawyer Martin Bennett: “Do you accept that the Claremont serial killer killings were random attacks
Sergeant Moore replied that he did not accept that: no, I can’t accept that proposition."
https://www.theaustralian.com.au/...claremont.../bbca989cb476faeb057b042380826366 the link is only available for subscribers.
The idea that perhaps the accused knew the victims and perhaps even groomed them eg with JR and her work location proximity to the cemetery.
Having 2 factors put together such as not random and the girls leaving alone could mean that there were other girls groomed but perhaps there was never an opportunity where they were alone. It could also mean that perhaps a suggestion that it is better to catch a cab/phone a cab near Stirling Highway and the girls are alone ready for the taking.