Shipping Multiple Packages

We are shipping items from our PC store via the UPS integrated shipping center.  We run into a problem, however, when someone places an order that needs to be split into multiple packages.  For example, if someone orders 40lbs worth of merchandise, and some of those items are bulky or fragile, we may need to split that order into 4 boxes.  Even thought the weight is the same, UPS will charge significantly more 4 boxes at 40lbs than just one.  The cart, however, has only charged the customer as if its one box. 

I can't seem to find a setting or function in PC that will handle this issue.  Has anyone else had a similar experience?  Any suggestions?

Thank you for the response.  We did play around with that a bit.  The problem is that one of an item is not enought to warrent it's own box.  For example, (we sell italian specialty foods), one or two cans of tomatoes doesn't need it's own box, but a case (12) does.  Or, if there's an order for 6 cans and a few pkgs of pasta, we will want to split those as well in order to keep the cans from crushing the pasta.

So i can't mark a single can as oversized b/c then UPS will charge for a new package for each can.  If I create an item for a full case and mark that oversized, it still doesn't cover the other scenario.

I think I have two choices:

1. Set a limit on the product level that will tell the system it needs to be it's own box, (i.e. 6 cans of tomatoes=oversized) - OR -
2. Set an average weight limit per box.  (Let's say the limit is 15 lbs, and the order is 60lbs, UPS will calculate this out to 4 boxes.)

Either way I think I'll need to custom code a solution.  I just wanted to be sure there wasn't already a tool in place before I went through the trouble. 

Thank you, Stuck.  I believe that's exactly what I'm looking for!

I don't mind admitting that I feel a little foolish.  You know, I've bee struggling with this for two weeks.  I've been all through the backend and manual looking for a solution - including, of course, the shipping settings.  The whole time I was thinking, "PC is so robust, it must be here somewhere!".  If it was alive, it would have bit me it was so close!

Thanks for pointing it out to me.  You saved me alot of time.