Joint Curves

[jacob.d.nielsen]

Hello everyone.
I want to ask you all for advice.
I have the four lines that I would like to “gather” like the ones in the middle of the picture.
Can you help?

[cgartland]

Try joining the middle curves first and then, rather than translating, offset them. This will keep the curves joined.

[jacob.d.nielsen]

Yes it works. But does not give the result I would like.
In this case, the curve offset must be at different distances.
Wall thickness / 2.

basically i would like to extente the curves. So end points are = start points etc.