merge two loft/surfaces into one, split between surfaces

Hi!

I am trying to combine two loft surfaces into one where the surfaces "meet".

Now I made two loft surfaces, but they are overlapping. I want to "delete" the overlapping parts so that there is one surface.

How can I solve this problem?

I want to split them, or merge them in some way.

I attached my files, the part with the loft is by the yellow square.

Thanks in advance!

Maria