The easiest way is to bind all orchestrations to the receive port that receives these messages. All orchestrations will receive the same message type.
In the receive shape filter of the Order orchestration you will need to add
YourPropertyNamespace.Subject=Order
In your property schema you will need to set the Subject property’s Property Schema Base to MessageContextPropertyBase
If the property schema is not in the same project as the orchestration you will need to add the assembly containing the property schema as a reference to you orchestration project.
You can also use direct binding on each orchestration, this may require a more complicated filter set up.
I have a similar project, although I have used a map to convert the name/value message into a tag based message rather than a custom pipeline component.