Remove individual instances in an array? Hey guys

I'm somewhat new to blender and modeling in general. 

I'm trying to find a way to remove some instances in this array without having to apply the modifier. I want to have just the twelve spikes (marked green) but still have the benefit of only having to edit one to change all of them.

Is there a way to do this?
How about using the Array modifier for one side (8 of the spikes) and then a Mirror modifier to replicate that on the other side?