Need for an advanced lookup and format formula/macro

Estimated duration: 1 day
Description: I have a spreadsheet with products and their details. Some products have variations of size which are added at the end of the SKU (product code). I need some automated way that a SKU with size options has a parent product (holding product for size variants) created.

Example:

in the products we have

128
534K
11222S
11222M
11222L
11678
11333M
11333L
11333XL
11333T1

From the skus above, the automation would need to detect the products 11222 & 11333 have size variations and a parent item would need to be created with SKU 11222 and 11333 and the rest would be ignored.

I would guess that a formula like below would need to be created:

IF [Check if product has any letters in the SKU]
THEN [check if the product has others with the same numbers]
THEN [Create SKU with just the numbers]

obviously this would need to skip the other child SKUs so as to not create duplicates.