Specific items only in a container?

[Legacy_Buddywarrior]

                I'm making a bag to hold magic cards, much like runes. I only want these cards allowed in the container (a weight reduction bag) . What is a good way to only allow certain items in this bag? The resref and tag for each of the cards going into the bag are all card101 card102 card103 etc. 
               
               

               
            

[Legacy_Lightfoot8]

               There is no way that i know of to restrict what a player can place in a bag.   The best work around  I can think of, Would be to not use a bag at all but a tag based item.   The TBS for the item would SpawnIn/Open an invisible  container placeable that you could place your item restrictions on.