You may be able to display a genric label which cover all operators. Check with the vehicles hire authority in your state. It is perfectly legal in Victoria.
In Queensland you have to provide one for each ride-sharing service you're affiliated with and it has to be the approved sign that they make.
Insane lol. Didi and taxify are about to start operation in QLD soon. What happens then? 4 stickers?... and what about GoCatch, Muve, etc. I have no doubt they'll have to change the legislation to displying only one genric label. Watch and see. Many more ride share companies are coming, its crazy.
Good news! More options for you guys. Taxify are pretty good long distances. I love thier airport runs here in Melbourne.