Karamba, settings nodes between principal and secondary beams

Hi everyone,

I am trying to model a simple structural frame with 4 columns, 4 principal beams and 4 secondary beams which should be connected to the 2 longest principal beams as you can see in the image I attached.
I am having problems with the definition of the hinges between the principal and the secondary beams, as you can see the secondary beams float in the air while they should be connected to the principal ones and follow them as they bent. 

Does anyone have some suggestion on how to solve this problem?

I attach the Image and the .gh definition I am woking on.

Thank you guys.