what is your use case? As the standard configuration is to have a publish instance receive content from a single author instance. you can have a singe author pushing content to many publish instances.
Yes Opkar is right.
You can have single author instance and many publish instances. Single publish instance is not at all recommended.
I think it should not be an ideal case to have multiple author which pushes content to same single publish instance . Imagine the scenario of having a conflicting situation where same node modified from both the instance is pushed at the same time. The content will get conflicted and will never give you the intended result. I think you shud rethink the solution for your use case. Could you please tell what is the use-case for which are planning for this solution ?