Use Item Product Group (Color Number to Item Number) - System Option

>Utilities>System Options>System Wide>Inventory>

Category-Configuration

Type- Must be Global

Default Value is No.

This option similarly allows handling item products as roll products, when
a single item record has multiple colors/descriptions.  Using this feature will ensure
that the correct supplier's item number will be used on purchase orders because the
description number is used as an item number.

For more information, see Item Products Group.