You can use Sling Content Distribution to meet the above requirement . This distribute Sling resources between different Sling instances. This can be used to distribute/sync content between AEM Author and Publishers for different scenarios.
"pushing" from Sling instance A to Sling instance B
"pulling" from Sling instance B to Sling instance A
"synchronizing" Sling instances A and B via a (third) coordinating instance C
Also to answer user question, when multiple users submits at same time to different publisher, content will be pulled and synchronized between all the publisher instance.
For more details please have a check on below documents