We consider a problem of grouping orders for batch processing that arises in production systems where customer orders are processed in batches. This problem can be viewed as a variant of bin packing problem where items can be split and a pair of items can be placed in a bin when the items are compatible with each other. In this paper, we consider a special case that at most two different items can be placed in a single bin and the size of every item is at most the size of a bin.