In a Combine region multiple items can enter the region through:
Separate region Entry Transition Indicators and reside physically on the same Item Carrier in that region.
One Entry Transition Indicator by PRT receiving multiple notifications from the Transition Indicator. The Items themselves are in no way required to be associated.
Required for Combine regions
A single Exit Transition Indication is required from the region.
The region must be configured to have a region capacity of one.
Positive Item Type detection is required for each Item entering the region.
Allowed in Combine regions
The Items merely reside on the same physical carrier, they are not required to be associated in any way.
Multiple region Entry Transition Indications are allowed.
It is not required that all Items arrive at the region before the carrier exits the region. The Items that arrived at the carrier before a transition out of the region is detected are the Items that moved together with that carrier.
Other rules for Combine region items
A Tracking Region designated to execute automatic Item Associations must be a Combine Items Tracking Region.
Secondary region types.