First Class duplicate costs woes...can you help?

[thedukesawparts]

Is there a way to make the system automatically calculate FC postage into Priority when it goes over the weight threshold?

Or automatically combine FC items and Priority items together so buyers don't get duplicate charges?

Thanks!

[disneyshopper]

I use Calculated Shipping, and have a RULE to add the weights.

This works well when all items ship using the same method.  It doesn't work very well when the items ship using different methods, but I haven't lost too much money when this happens.  ebay will simply add the shipping costs together for each item, but the invoice can be changed if the buyer has not yet paid.