I previously did group buys with Roger Chartier at masscashsales.com in the USA. Even with shipping and import duty we managed about 45% discount over UK prices, so a worthwile saving - i bought about $800 worth on that transaction. The last deal i did with him was a few years ago for 3 tubs of Ital wax, they came out at about £38 a tub as he was clearing stock, the UK price then was a ridiculous £325/tub, although its now back to a more reasonable £120/tub now !!
his old website seems to be dead now, but i think he is resurrected on...
http://zymol-central.detailbest.com/Certainly worth a try if you are thinking about a group buy.
I originally approached a few offical Zymol sellers in the US and none would export to the UK as there were official UK based sellers - Roger didn't have a problem, if he is more tied in now with Zymol US then this option might now be dead.
Just back from 2 weeks holiday over there - wasn't really looking out for it, but didn't see it sold anywhere, like the UK its a bit specialised. The abovelink will deliver to your US hotel though, so bringing back in luggage allowance is viable.