The site should have a feature to allow setting a max bid for a group of items, and optionally taking into account shipping price. Otherwise what is the point of groups?

I'd be happy to try implementing this myself if the software is open source or something.

Please avoid submitting your question multiple times. It will not speed up the response, but may add an extra confusion to you.

As I mentioned in my other response:
You can add items in bulk using browser's extension when you click on the "Snipe these" button located on the Search results page.

Shipping depends on the destination and some sellers may offer multiple shipping methods. Even eBay does not accept bids with shipping price included. That's always extra when you pay for an item.