Ohad here, from Zoorix. We have a similar solution in the app that enables you to offer discounts based on collections. It’s not exactly the same as what you are looking for, but it’s similar enough so I thought that it might help.
Here is an example of how it works - if the customer buys 3 items from collection A and 3 items from B and then she gets a 10% discount. The customer can also buy more than 6 items, but the discount will be applied only if she buys 6 or more. The numbers in the example can be changed, so it can be 3 or any other number for each collection, and also the discount can be any percentage and also a fixed number e.g. $20 off.
Hi @olnerpsm ,you can simply do this by going to your Shopify admin and go to Discount and create either a static or dynamic code(dynamic is recommended).When setting it or after setting it up,you can specify
the dates for which the code is valid
the number of times that a code can be used
a minimum order amount before the code can be used
which products, collections, or variants the discount can be applied to
i hope this helps but if you have any problems regarding setting it up or you will like me to help, kindly let me know.