Adjust position of a relative guide

I have a guide step that is set relative to an element, positioned below it. The element spans the page but only contains content for about 1/3 of that width - this is the only option for an element. Because the guide centres on an element, it looks like we're pointing to something that doesn't exist. Is there a way that I'm missing to nudge the step to the left but still keep it below the element? Right and left are not options.