Joining a lot of contour lines but just the ones that have the same z-height

I have this problem: I have used ArchMap to make alot of contours from GIS data. The contour lines that are created have this cut and doesn’t exactly join. It is visible enough to be enoying.
Is there a way to connect them horizontally in z height quickly without making a mess?

if you look in from the front or the side view and select the curves you can use align to bring them to the same height. that is of course a bit an effort if you have hundreds of curves.

but i am fully sure i udnerstand your request, to judge or to help better a screen shot and a file would be good.

usually you would do contour lines with the contour command in rhino which then groups the curves on the same height if needed.