if this was me, and bear in mind im not realling looking at your drawing, i would just pick a lane down the front that offers the least disturbance, and rip a new supply line, 2" or 3" or whatever, and then fix it all after. tie all of the valves into this new main and run it off a new tap that will supply the amount of volume needed. dont make it harder than it needs to. and at the same time express to the HOA that there is going to be a substantial impact to the landscape. and not to be a prick, but from you line of questioning, it seems you might be in a little over your head on this one, is there someone in your area with a little more experience that you could call to consult or sub out to?