JMSOrderException when sending message on distibuted queue

My environment is an enterprise application deployed on a cluster composed by 3
server.
All jms queue are distibuted on cluster using load balancing policy (Round-Robin
or Random) so all messages sent are distributed equally on Servers...
When I want to process messages that require a serialization dispatching I use
Unit of order like:

((WLMessageProducer)(sender)).setUnitOfOrder(unitOfOrder);

This ensures that message will dispatched only by one server of the cluster so
the serialization is guarantee!

But if one of the 3 server is down (it may be possible on cluster environment)
sending message using unit of order rise this exception:
weblogic.jms.extensions.JMSOrderException

For example, if Server 3 is down the message exception is:
weblogic.jms.extensions.JMSOrderException: hashed member of
!! is
!!3@ which is not available

If I use a Random load balancing policy is possible that the hashed member
result is a started server, in this case if I'm lucky it works! But It must to
work allways!

I will appreciate every advice!