You mean like groups?

oh, that's helpful, thanks.
yes but you can only merge down
I can select a layer that's fifteen layers above another layer and merge the two
photoshop master race
lol you can just move the first layer you want to merge above the other.
i'm not denying that photoshop is better, because i'm damn well positive it is, i'm just saying GIMP can and usually will get the job done in almost as many cases as photoshop.