Change Dynamic material parameter within loop?

Hi, I have a loop in which I draw several textures using a material to my gui. Now, I want one of those colored in. The obvious answer was to change a scalar parameter for that specific instance of the draw calls. Now, it seems that the calls are grouped and prior parameters are ignored when using DrawMaterial, since either all icons are not colored, or, if the last item is selected, ALL items are colored. Do I have to create a second instance of the material in order to render mutliple items with the same material but different parameters ?