How to please both european and american customers? Shipping from USA to Europe costs an arm and a leg... Card is 3 dollar, shipping is six dollar... Making sense? Nope... How are we supposed to sell cards with those prices?
With our Pro account, you can use any of our labs. You can choose a different lab by creating a new pricelist in the 'manage pricelist' screen of your account settings > business > making money section.
At this point it's not possible to offer the customer a choice of which lab they'd like to use. You could only create separate galleries for your US and European customers and apply the appropriate pricelist to each gallery. Yes, that would mean you would have to upload the photos twice, but right now that's the only option.
For additional information on using pricelists, check out the pricelists help page.