Hi Sam,

Think of Alternate items as being part of an 'item set'. In fact, that is how it works - use the Column Editor on an item grid and add the 'Set # key' field. If this value is 0 then there are no alternate items defined. If this value is non-zero, then it can be an alternate item with every other item that has the same value. Essentially this field 'groups' items into Alternate item 'pools'.

So in Andrew's example, items A, B, C and D are all alternate items with each other. Check sample data and there are mant set up, including groups with more than 2 items (the KAK items).