How do you combine all troups?

[jake21]

There are several situations in which I will end up with two stacks. I want to combine the two stacks into one. However, when I click on the stack and get the (<->) thingy that allows me to merge them I can make at best two stacks of 1 and n-1 and then dismiss the one. I cannot find a way to make 0 and N which is what I almost always want (this is also true when moving from reserve to stack).