A way to target weld by whole loop to another loop

[soswow]

See this scene. There are two objects (separate shells).

They have two loops each. I want to weld every two corresponding edges together. And what is important, I want to 

edges of a bottom object to weld into edges of a top one.

See from the side:

You can see top object has bottom edges all ligned up. Basically I don't want them to in the middle.

the only way I can see right now is to combine two shells and then do target weld one edge at a time.

[Christoph_Schaedl]

Use bridge and ring collapse.

[soswow]

I tried googling and using the search function inside Maya itself. Mind explaining what "ring collapse" is?

[Christoph_Schaedl]

Its in the edge marking menu on the top. 

[Christoph_Schaedl]

Made a video. 
You need to combine the objects first.

https://youtu.be/lV022fqLN0Y

[soswow]

Right. Thank you for recording a demo!

Thought I specifically said 

> And what is important, I want to edges of a bottom object to weld into edges of a top one.

It would be even better if I said top edge loop should come does and merge with corresponding edges of a bottom edge loop. Imagine that that jagged form of bottom edge loop is an important one. I knew how to merge them "in the middle", hence asked that question.

[Christoph_Schaedl]

In that case. Bridge, slide edge and merge.