I would like to calculate my revenue growth with a simple percentage of the prior months revenue (=C10*0.2+C10) across a 12 month basis. However, I calculate totals on a quarterly basis. I would like to have my formula skip my quarterly total columns.. in this case F, J, N so that I can drag my formula across 12 months and not have my quarterly totals effected. Is this possible and how?

Thanks!