It’s usually best to place the behaviour in the stage either before or after the behaviour that you have a dependency on.
See Steps, Stages and Connectors • NServiceBus • Particular Docs for the list of available stages.
Should that not be possible we provide an API for ordering behaviours within a stage by implementing a RegisterStep mentioned in Customizing Error Handling • NServiceBus • Particular Docs and from the call one of the InsertAfter, InsertAfterIfExists, InsertBefore or InsertBeforeIfExists methods.
Hope this helps!