Set seperate handling charges for perishable's and non-perishables at checkout

Question

I've run into a problem trying to set up some appropiate handling charges on two different types of products: Perishables and non perishables.
I've tried setting it up through categories in the shipping options, which works great up until I try to purchase both a non perishable and a perishable product at the same time. When I have both these items in my cart, no valid shipping option is given. (probably because I set the categories handling charges to exclude the other category as I dont want it as a shipping option if customers only purchase perishables or non-perishables, and it is shown to customers as an option when its set up in this manner!)
Example:
Perishables hold a $12.00 handing charge per order, non perishables hold a $6.00 handing charge per order. If I set up shippng options for only Non-parishables by excluding any Parishable category, and do the same for Parishables by excluding any Non-parishable category, im not given any valid shipping option when my cart contains both of these. My question is, how can I set it up so when my cart contains both of these types, there is a desired shipping option (while at the same time not including this option if the customer only purchases all perishables OR all non perishables)
My apologizes if this comes off as confusing, I've been up for a while now trying to get this to work! Any help or direction would be appreciated.

Answer 1

I noticed a somewhat similar question just now which contains no workable answer, argh! Ill leave this open for a little while but will move it to the code section if no answers are submitted as the only workable theory I have come to involves javascript.