question

Hey @Navid M, here are some things you'll need to work out to achieve your desired outcome.

First, you'll need to have a way to keep track of Order Numbers and Racks - you could achieve this with a Global Table that you update with some Custom Code, something like this:

/**Custom Code*/
Object current = param(1);
treenode activity = param(2);
Token token = param(3);
treenode processFlow = ownerobject(activity);

Table rackLookup = Table("Rack Lookup");
int orderNumber = token.Item.labels["Order Number"].value;
int row = rackLookup.getRowByKey(orderNumber, "Order Number");
Storage.Object rack = rackLookup[row]["Rack"];
if (rack) {
  token.labels.assert("Rack", rack);
}
else {
  Storage.System system = Model.find("Tools/StorageSystem");
  int leastItems = 2147483647; // int max
  for (int i = 1; i <= system.storageObjects.length; i++) {
    Storage.Object tempRack = system.storageObjects[i];
    int numItems = tempRack.subnodes.length;
    if (numItems < leastItems) {
      leastItems = numItems;
      rack = tempRack;
    }
  }
token.labels.assert("Rack", rack);
rackLookup[row]["Rack"] = rack;
}

The Rack column will be updated based on the number of items currently in that Rack.

Then you'll need to have some sort of trigger to know when you're finished storing a specific order. This could be accomplished with another Table that keeps track of Order Number and total number of packages in that order (or you could do a calculation every time on that table you provided). Then you have a Event-Triggered Source for when an Item enters a Rack. You can increment a counter for each Item and Type in that same table, so it looks something like this.

and the Total value could be like this:

Table ArrivalTable = Table("Arrival Schedule");
Table TotalCount = Table("Total Count");
int total = 0;
for (int i = 1; i <= ArrivalTable.numRows; i++) {
  if (ArrivalTable[i]["Order Number"] == TotalCount[1]["Order Number"]) {
    total += ArrivalTable[i]["Num Packages in Order"];
  }
}
return total;

You could also just keep a hard-coded Total instead of calculating it each time.

Once your current count has reached the total, then you could spawn a token in another part of the Process Flow to trigger unloading of that item type.