Queue call should wait for speaking agent


I have a problem with the queue configuration.

The queue has several static agents. If there is a caller, all phones should be tried one time. If no one accepts the call, the caller should be sent to the failover destination. But when an agent is still speaking, the caller in the queue should wait till the agent is again available and could be tried one time.

I have tried various configurations, but none has done his job properly.