Task Exec - pick up object without destination?

I have a system I am modelling. It takes in 2 empty pallets. when one of the 6 palletizers it services creates 2 FULL pallets, it goes there, drops off the 2 empties and picks up the 2 Full.

Then it transports the 2 full pallets and drops them at the stretchwrapper and picks up 2 more Empties at the same time.

The problem is that I don't know the destination of the empties when I pick them up. In an ideal world, I could wait until there was a full system ready and then get empties, but that isn't how it operates and I actually have 2 of these operating in the same space.

Any suggestions on how to approach this?

If you want to do this with as much default behaviour as possible, using just opening and closing for ports and hardly any flexscript or triggers this model might give you some ideas.

For speed I've just considered one pallet being delivered. It's a little deviating in approach, because I placed a queue in the transporter and the flow rule on that queue determines if the pallet can go to any port (when the pallet is empty) or just the finished pallet queue (port 7 if it's full). The finished pallet queue also checks (in its pull rule) that the pallet has items loaded to avoid the transporter taking empties there. When an empty pallet is unloaded at a palletiser it closes the input. When a pallet it finished it opens the port that was previously closed.

It needs refinement to cater for two pallets at a time and also to make sure the cycle is followed in strict sequence - at the moment it can unload two full pallets from different palletizers before collecting empties to replenish them.

As a 'quick and dirty' workaround, I don't think it's a bad approach - although the content related statistics of the transporter will be wrong since they will believe it's always loaded.

To do the task properly you might want to adopt a more agent-based/self-determining approach where the task excecuter generates its own jobs and evaluates the conditions of the system.

This is excellent. Just the example I needed.
I was wondering how to both connect to the queue if it was embedded (doesn't look like it is any different) and how to direct my flow.

Thank you so much!