Stock Allocation

[Phil280372]

Hi I'm new to the forum and need help with a query, I have 2 tables first table containg a list of items and available "quantity" stock the second table order lines for the items contain in the first table, What I want to do is allocate the order lines where stock is available until the quantity is exhausted and identify the line as available to pick for line where the item exceeds stock available I want to allocate the line without exceeding the quantity available and indicate with a yes and for those lines which exceed the quantity show as not available.
I can show where stock is available but it allocates lines which exceed available stock how can I stop this?
Many thanks in advance for any help / assistance