Being in supply chain, we deal with this all the time at many different companies.
engineering wants one SKU. keeps it simple. one spec.
Procurement wants multiple vendors. and they want to split the business, sometimes every other order, sometimes by %.
the best and easiest way to do that in an MRP or replenishment system is with different part numbers, and dividing up the demand appropriately.
you typically can't have more than one vendor for the same sku, or the system doesn't know how to dreate the purchase orders. some systems have customizations to do that, most off the shelf software does not.
from a planning perspective, it is always easier to manage and when you have separate sku's.
and if it is an item that needs to be controlled for recall or other purposes, you need to know which supplier to go back to when their is a problem...