Because you need to configure that in the aggregate queue as well.
The problem, from whaty I can understand, is that there is only one alarm, and that is per queue and not, in case of composite queues, per member of the composite queue.
That is, if you have queues
A and
B each with their own analrm levels, you
can create a queue
A|B and set an alarm level for all calls in
A or in
B, but the alarm levels defined for
A or for
B will not be shown when seeing
A|B.
Is this the problem you're trying to solve?