shuffle two different loops

I am working on two loops, each pulling 5 posts from their category.

The loops have a simple float:left, now I am trying to find a way to exchange locations from one loop to another...

Basic layout would be something like this

1 2 3 4 5 ( posts from category numbers )

A B C D E ( posts from category letters )

What I am trying to make would be something like

1 2 C 4 5

A B 3 D E

I can use position and move them by css3 hand but that would give too much additional work with responsive design.

Thanks