There are a couple of ways to do this that I am aware of. Both involve creating a layer group of the layers that you want to step up, but it sounds like you're doing that anyway...
The first option, which has already been alluded to in the comments, is to use actions. Simply record an action of whatever you do to create your first step and then keep replaying that action until you have the desired number of total steps.
The second option (and my preferred method for straight horizontal or vertical steps) is to duplicate the layer group the desired number of times, move one of the copies to the last step position, select all of the layer groups and then use
Layer > Distribute to evenly space the layers. The benefit of this method is that you don't end up being out of position at the last step if your chosen step size if slightly off or gets messed up by rounding, pixel snapping, etc.
In either case, if you need to step in two directions, simply do the rows or columns first, make a layer group of the stepped up layer groups and go again.