Bridge surface

Hello,

I'm trying to create a radius between 2 surfaces on a 3D-impeller.

I created the 2 surfaces, they're seperate from eachother. But I need to connect them at the top with a smooth radius. I used a bridge surface to do so.

Everything is fine so far. But when I extend the sheets, so they can be trimmed on the hub/cover plates.. the surface bridge comes loose from the other created surfaces:

The bridge surface is created on sketched, straight lines. As are the connecting surfaces.

Is this not the right method to achieve what I need, or should I use a different feature perhaps? Any tips are welcome.

Edit: To clarify -> I need the surfaces to connect together so I can create a solid body out of it.