How to run robots based on load in multiple systems

We have three robot licenses and we have 4 automation packages needs to be executed by orchestartor with three licenses. I configured three robots with three automation packages and schduled for every 5 minutes once and now I want to configure the 4th automation package on all these robots (instead of one specific robot) , so that my intention is , 4th automation package should execute by any one of the 3 robots when every there is a time gap to run.

How this can be achieved through orchestrator ? Configuring 4th package on all three machines will solve issue or any suggestions ?

You can use Orchestrator API to get the details of next schedules.
Based on schedule details you can apply logic check to check to check the ideal time to run the package in that particular bot .
Use API to trigger the package on that robot.
You can make use of API to get bot status as well.

Please let me know if this works for your requirement.