Both facilities held different sub species; Melbourne (C. g. guereza from the UK) and Perth (C. g. kikuyuensis from the USA).
I could be wrong but I thought Monarto's animals were descended from the Perth zoo stock. I know Melbourne used to have quite a large group of Colobus's too, so it's also possible Monarto's animals were also descended from Melbourne's former group.
Or perhaps from both facilities - the Exotic Mammals thread mentions the two sub species were later mixed, ie. the male from Perth being sent to be Melbourne's previous breeding male in the 2000's. It's possible individuals from both Perth and Melbourne were sent to start Monarto's group at the same time.
The male in question was Brodie. He was Perth bred and transferred to Melbourne Zoo in 2005.
His offspring were:
1.0 Indi (2006)
1.0 Colby (2009)
1.0 Colin (2011)
0.1 Kipenzi (2012)
His three male offspring transferred to the National Zoo (with Colby later returning). Kipenzi of course remains at Melbourne Zoo.