Hello friends, this is my first post in the forum!

I am working on my first project on Revit MEP and I have a problem with modelling my duct system.

I have a system with 2 AHU's connected to each other. Part of the air exhausted from the first AHU passes through the second one before supplied to the floors above. How can I model this, concidering that the duct connecting them is a supply duct when concidering the first AHU and regarding the second AHU is return?

Thank you!