Item substitutions on orders

Hi All,

We have an extensive need for maintaining item substitution logic.  Basically we can allow substitutions based on a table - one product could have multiple other products that could be subbed for it.  I only see a line on the item for one alternate product. 

Also we would like to automatically feed in the sub to the order, instead of being prompted to change.  We would also like to notify the customer when we use a sub instead of the originally ordered product - we want to send them a report daily of any subs that we used. 

Any ideas?

Thanks!