The previous-queues Attribute
Specifies a list of queue IDs separated by commas. The default is the empty string "", which means there are no dependencies on other queues. If you specify one or more queue IDs, transactions on this queue will not execute until each of those queues are inactive, disabled, or empty except for transactions that are being held. Separate a list of queues using commas:
Parameter name="previous-queues" value="queue3,queue5"