Help getting started with a Cross-Dock!?

I need to build a cross-dock (crossdock, x-dock, xdock) model.
The issue I am facing is that a cross-dock works slightly different than how most FlexSim models I've seen do.
I apologize in advance for the lengthy explanation below. I don't know how to explain this problem in less words.

In a typically model there is a specific input and a specific output. The two do not interfere with each other. An item flows into the system and eventually leaves the system.
However, in a cross-dock the doors of the building are seldom dedicated; meaning the doors are shared amongst the input and output objects/items. In other words, a trailer arrives at door 1, gets unloaded and the product is staged at or loaded into door 2. Later on in the day door 1 may act as the outbound door instead of the inbound door.

So, how do I make a model that has a source and a sink next to each other (they represent a door that can do both inbound and outbound), but when the source is active (represents a trailer being unloaded) the sink is unable to accept any objects/items and when the sink is active (trailer is being loaded) the source is blocked.
Oh I almost forgot, multiply that by about 30+ doors that can do inbound and outbound and 30+ queues.

We deal a lot with situations like this, so if anyone has a suggestion on how to dual utilize a door, I'd appreciate the help.

Sven,

If you want to model the doors wih source and sink then I would suggest connecting them with center port connections and then use logic to close the output/input of the other object at certain times. So, if you want the door to be input then close the input to the sink and open the output of the source. If you want the door to be output then close the output of the source and open the input of the sink. This logic will work even if you choose not to use a sink and source for the door objects.

Another way to do this would be to use one object like a processor or queue and then use pull logic to only pull from port 1 or 2 (depending on direction) and then in the flow logic send the object out of the same port number.

Good Luck,
Brandon

Can you post examples of both of the solutions you are speaking about?
I've attempted to do them on my own without success.