Here is one suggestion:
BrokerAdminClient API has a method called getClientStatsById(). It takes a particular client and returns BrokerEvent. This broker event has an integer field field containing the queue size in bytes:
(BrokerEvent.getIntegerField(“queueByteSize”))
You can try and work around these two APIs to manipulate a single document queue size based on the particular client broker document subscriptions.
HTH
#Integration-Server-and-ESB#webMethods