You can set up the item as a single item (Master data)
"T-shirt package of 3"
Items per purchase unit = 1 (Purchase tab)
Items per sale unit = 1 (Sales tab)
What does this mean?
Suppose you want to buy 60 shirts, you will have to purchase 20 packages and that's what you will write in your purchase order.
This also means that when you create the Goods Receipt PO, you will type 20 and not 60
Your inventory will show "20 items" and that means you have 20 packages of 3 shirts (I think you can use teh Factor fields in Purchase and Sales tab to specify how many sub-items come within every package but the inventory AFAIK will show 20)
There are variations to this, only thing you have to be carefull is the results in the purchase orders, the inventory and the sales orders (buying 1 shirt instead of 1 package, selling 3 packages instead of 3 shirts, stocking 3 packages instead of 3 shirts, etc)
Possible variations
"T-shirt" (Not a package)
Items per purchase unit = 1 (you buy the exact number of shirts you need)
Items per sale unit = 3 (you type in the sales order 1 and it will automatically reduce 3)
"T-shirt" (Not a package)
Items per purchase unit = 1 (you buy the exact number of shirts you need)
Items per sale unit = 1 (you type in the sales order the exact number of shirts sold, say 3 or 6 or 9 or... 11)
is you buy and sell packages, maybe it's better to save the master data as "Tshirt package of 3" with 1 and 1 in PU and SU
Try it on a test database and see how it behaves. Let us know if this works for you
