Order splitting automatically accross multiple warehouses

We are using Oracle OMS and Oracle WMS for a 3PL setup. Some type of our customers have multiple warehouses but do not specify which Warehouse to ship from. A hierarchy table is provided with postcodes ranges for system to look up the closest warehouse. System should check inventory in this hierarchy. If not available at the closest warehouse system, solution should revert to the next warehouse in the hierarchy for order creation. Sales orders may end up being split accross multiple warehouses.

Before we start customizing a solution, I wanted to check if anyone had used anything existing or a best practice.