My opinion is don't. They won't get it, and if I'm frank, I think you're only considering this tactic to try and intimidate the other parent and get more taken away from them, rather than get more time granted to you. Regardless of your personal reasons for entertaining this avenue, I will provide legal reasons why you shouldn't waste your time.
First, how many orders do you think a child should be subject to before it stops being in their best interests? Two? Three? Five? Every first weekend with dad, every second weekend with mum, every third weekend with Aunty Maisy, every fourth weekend with grandma?
That is absolutely ridiculous, and no court in Australia will even consider making such a convoluted mess into orders. If your family wants to spend time with the child, your tactic should be to seek as much time with the child as possible so you can facilitate the child spending time with them during the child's time with you.
Second, the level of proof required to show that they should have orders for the child to spend time with them is significantly higher than it is for you and the other parent. It's not just the child's best interests. They also have to show they're a person concerned with the child's care, welfare or development, and that they have a relationship with the child that is of such significance that orders are necessary.
Third, you're going to be seen as frustrating proceedings, which will immediately put you off side with the judge. It's highly unlikely the judge will even grant leave for all of these random family members to join as respondent's, but even applying is going to make it very difficult for you to show that you're concerned only with the child's best interests when you appear to believe the child should be subject to three or four different parenting orders.
Rethink your tactics. Apologies if this is blunt, but I get extremely tired of parents who think they can manipulate the court to "win", instead of just thinking about what's best for their kids.