How to handle Item with multiple GST - HSN code?

In a company where we are implementing ERPNext there is a situation where they have a few (steel) raw material items used as input for manufacturing.

This items comes from different suppliers with different HSN code.

What we have done is created one Item for each different HSN code.

In the manufacturing process it is used as base raw material and we have used it in a few BOMs. Currently we have to create different BOMs for each base raw material. This is resulting into lots (160+) of duplicate BOMs with just the base raw material changed in each BOM.

Due to this users are making mistakes when selecting BOMs at time of creating Work Order.

Can someone please help me in implementing this?