1. A method for collating items into at least one ordered group from at least two subgroups using a processor, modules for supplying items and a mechanism for transporting items to an output destination, said method comprising: (a) arranging the at least two subgroups such that items are in order within each of the at least two subgroups; (b) placing each of the at least two subgroups into corresponding modules for supplying the items; (c) controlling a module for a subgroup containing an item of a first ordered group to be supplied to supply the item at a given time to the mechanism for transporting; (d) repeating act (c) until all items of the first ordered group are collated; (e) checking the order of the items as they are transported to the output destination; and (f) performing error-correcting routines if an error is detected.