create a light and ventilation schedule

Has anyone created a multi-category schedule with shared parameters? I'm trying to create a light and ventilation schedule which is a code requriement here in IL. Essentially the square footage of glazing in each bedroom needs to equal 8% of the room floor area. SImilarly, the ventilation square footage (window opening) needs to equal 4% of floor area. Seems like X4 should be able to handle this within a schedule. However, I can't figure out how to get the Area parameter into a window schedule so that I can do the math. Grouping and filtering the windows isn't a problem if I use a multi-category schedule (group by room, filter for only windows that have lite/vent variables). But, the area of the room is not an available field in the multi-category shcedule. If I start with a room schedule then I have the Area filed and can create shared parameters but I can't figure out how to bring in the window instances. SOmebody must have done this? This is a fudnamental requirement for all buildings in IL and it would really stink to have to export to excel to do the silly little calculation when it appears X4 should have this capability. Any thoughts would be much appreciated! Thanks.

Sounds like a job for Ruby, but someone needs to program it.

This would be a nice feature...if Ruby can do it sweet...even a simple spreadsheet functionality could accomplish this.

Wow so you have to show those calcs on every room every time even if it is obvious it meets the requirement? I typically only show them when a room is just barely making those requirements. When I do show them (which is rare), then I just do it in a quick text box...but a more programatical way (if that is a word) would be great.

We have the same requirements in California, though not required to necessarily show the calcs for each room. It does sometimes come up as a plan check item. But, this kind of thing is definitely the future, should be regarded as good basic design regardless of code, and would be a great feature.