U Shape Lift Core Wall for the Pushover Analysis

[safakarslan]

Since Etabs doesn't allow assigning hinges to the shear walls, i am going to model those as columns and then edit with section designer.
Do i have to model the u shaped core walls as 3 single elements on 3 joints? If so, how can i ensure the connectivity between those 3 parts and the beam?
Or can i model those as a single object assembled from 3 walls? Same issue also for this case; how can i ensure the connectivity?

 

[safakarslan]

Forgot to mention; it's a 7-storey RC building.