Is your monthly project a repeating project, or do you enter them by hand? Why not bundle all of your monthly tasks into a template using Curt Clifton's Populate Template Placeholders script
here, make the tasks not repeat, and just stamp out new monthly projects as you need them? Or, maybe not have a monthly project at all (what is the goal of your monthly project?) and file those repeating actions according to what they are? For example, instead of having a project called August 2009 which includes actions to pay the water bill, pay the electric bill, etc. have a bill paying project or single-action list which has monthly repeating actions to pay the water bill, pay the electric bill, etc.