This thread is primarily for organizing box splitting between members for multi-item boxes. It also give people a place to mention upcoming spares they will have (which is closely related to splitting), or one-time or limited-time offers that would get overlooked or not noticed in time in the regular sales/marketplace thread. For example, if you have a pre-order you no longer want but are willing to offer it to someone else before you cancel it, you can look for takers here.
While we'll be monitoring the thread, the organization and transactions are still the responsibility of the poster and buyers. This should be done through PM on a case-by-case basis. So for example you might post "Hey guys I want to buy this box but I need people to buy X Y and Z or else it's not worth it. Please PM me if you're interested." The post in the thread would track what items are already taken (and by whom), and which ones still need a home.
Trust is pretty important here, because depending on the organizer, one person might be taking money from the others in advance and then buying the box, after which they'd ship out the items to all participants. It would be great if people would be willing to pay for the entire box upfront and take money for the spares after the fact (assuming enough interest is secured), but in this case the same risks exist in reverse. In any case be clear about your proposal, and as always, make sure you know who you're dealing with. If any problems begin to arise we may have to abandon this idea.