From within the Deadline AE Submitter, you can specify how many tasks of the job can run simultaneously on a single slave by setting the “Concurrent Tasks” parameter. This allows a slave to pick up more than one task (from the job) at a time. Be mindful of how much memory a task utilizes or if a plugin doesn’t support concurrent rendering. The After Effects Errors and Meaning section from the manual list a couple of known errors/issues.
Concurrent tasks will only work for image sequence renders, not movie file renders. If a slave has smaller hardware specs available, you can configure the concurrent limit for that particular slave to prevent issues.
Not recommended for this, but just to note, Deadline does has the ability to create more slave instances on a single node with an optional CPU Affinity configured. However, it can get very tedious to manage. Recommended to use the concurrent tasks parameter instead.
I’m sure others will chime in if I missed something. Hope this helps!