We use a lot of substitute items that being said, it wil be more practical if we have a button in IN-A where it will list all subs available for this item - and another button where it list this item substitute what.
 
now we have to go the the pick list to see the subs,  
If from IN-A I could tell what I could subsitute this part for or it subsitutes which part it will really help us.