You can create new SKUs directly in the Edit Product Group view. The new SKU will take on the same group attributes- like Title, categorization, and whatever other attributes are shared across the product group.
- Go to the Edit Product Group view for the product group for which you want to add a new SKU (3 vertical dots above the image).
- Select ADD NEW PRODUCT.
- Enter the SKU value for the new SKU, select ADD.
- You can edit the pivot attribute value for the new SKU from this view.
- Select SAVE to save your changes.
To edit this new SKU you can reopen the edit product group view and click on the new SKU. This will open up a new window with SKU where you can edit the price, list the SKU, or perform any other actions you might want to do.