Hey, we have a requirement where we can have a selection of nodes, foir a rough example say we call them:

10% Discount
20% Discount

Content editors can drag varients under the node they want the discount to be applied and associate them.  they will not live directly under these nodes.

What is the best way to prevent content editors from being able to drag a varient under more than one of these node?  E.g. if variant one, has had an association added to it under the 10% discount node, if a content editor tries to additionally create a second association under 20% discount they should get some form of warning.

Thanks!

Jon