Two possibilities come immediately to mind.
 Use air cannons, which can be activated manually or automatically whenever a bridge situation occurs. This should work, if bridging always occurs in the same place.
 Cut access ports in the each storage unit wall (requires a good seal system) to allow direct access to clear bridges.
There are other possibilities, including Rema's bladder system; the use of water; mechanical pushers and borers; and interior configuration alterations, but these are all more expensive and, in the case of water, potentially damaging to the product.
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