Rather than fragmented groups, get your Australiana posting in at the Aussie Zone Communities. No affiliation other than living in Australia.
Has cities, sports, politics so far and will add more as needed. It even has Perth and thankfully no Tasmania.
If you don’t have an account it seems it just uses lemmy.ml by default in Jerboa. If you want to use a different instance, you need to signup and then login.
For adding content from other instances, you can likely find it with https://browse.feddit.de/ (the built in communities search shows some but not all instances). Then e.g. if you’re using lemmy.ml adding cricket community from aussie.zone:
https://lemmy.ml/c/[email protected]