Personalized coupon for sellers at checkout

Hello devs, how are you? I have a problem and would like some tips to solve it.

When checking out a store “x” I have the native discount coupon option, and with it there is the option to enter the seller’s code. The seller code is custom, it accesses an entity in the master data to get the registered seller codes.

Is there a possibility to make this seller code apply a discount coupon?

  • I cannot create a discount coupon for the seller;
  • The discount coupon is an input and a submission separate from the seller’s code.
  • I need to avoid GTM;

I appreciate the help.