Oh sorry to hear your little one is having trouble. Hope she recovers speedily as your diet changes start to have impact!
Yeah I remember a short comment about subsequent children in the pamphlet we got when DS1 was finally diagnosed so I looked into it and while I couldn't find anything that gave a number for the likelihood that a subsequent child would have the same problem lots of people agreed it was fairly likely so I thought I'd just cut it out for a while to make it easier to check.
Would be nice if it was more advertised or if we knew how likely it really was. There was no mention of it from any of my care providers during the pregnancy or anything.
It's not so hard to cut out something for a while if it's likely to be an issue.
Sorry I don't know of any groups in Australia. I'm in the Netherlands now and the doctors gave me a list of foods off the shelf that were safe but really all the other mothers of children with sensitivities/allergies to dairy that I've talked to here have switched to specialised formula rather than make dietary changes...