Before ya'll get too far down the group buy path, which seems to be getting quite the wearing out lately. I'd also consider placing any group buy with either Cold River Soap Works or also Stirling Soap Company.
I've just done an order from CRSW (as they had 25% off) and it worked out at under $AUD17 per soap delivered from their classic/original lines. Though if you can get a decent sized order I'd highly recommend you consider ordering from their
Select range, which although at first glance seems scary expensive at $USD25 per tin - but it's 50% bigger than the classic/original and on paper should be the VERY BEST shaving soap in the world!!!!!
Yes, you read that right - the ingredients are literally the best I've ever seen (obviously thats only part of it BUT like I said ON PAPER!).
Plus they're always instock too - which is the killer with Mike's - you'll have group buys ruined or perpetually delayed as items will be out of stock for months and then sellout in a few hours!
I've had another Aussie recently place a big order with Stirling Soap and he raved about how good their service was in helping him maximise what he could get in his order to make it at a set postage cost. He'd also ordered samples etc in advance and said they were superb. They also have their own balms, aftershave etc so a tad more choice PLUS have some really unusual soaps e.g Beer!!!!! Added bonus is their soaps are all around 5 ounces and are just shrink wrapped - so you can really load up an order.
On your east/west coast order strategy I thought Aust. Post basically had a flat $7.20 minimum parcel charge regardless of location? So it'd be ideal if you could do a major city order then meet up to distribute plus perhaps swap a few other items.
I do hope you're able to get a group order placed with someone - I think Mike's is the best value, as his ingredients are just a tad behind the CRSW Select range in quality but much cheaper however getting stock in might require someone placing the order via email RATHER than his website - as he can give feedback on if/when he could fulfill it this way (I've emailed him before, really nice guy).