Your dependants don’t need to come at the same time as you.
Sometimes GPs decide to not bring their family initially, and while they settle into their new job and life, and then, in the future, arrange and pay for the actual visas of your spouse and children.
It’s a good idea to include all of their details in the initial nomination, because then you don’t need to make an additional nomination in the future. This is because when the practice adds the details of your dependants on to the original nomination, then you don’t need to pay for them to be added in the future.
Some info on Immigration: https://doctorconnect.blog/4db1ktR
*This advice is general in nature, and you should check with an immigration specialist https://doctorconnect.blog/3TuMV3i or the Department of Home Affairs.