Step 1 - Create one Related Product grouping on the Related Items template with one product in the ItemID field and the others in the grouping placed in the RelatedItemID field.
See the example below.
Note: For more information on setting up Related Items, click here.
Step 2 - Export your products from webmanager. Using this example, you would find the Related Items listed above on your product export and add the value in ItemID to the ShowRelatedFor field for each of the Related Items. For purposes of this example, I’ve removed all but the relevant columns on the Product template.
See the example below.
Step 3 - Once your Related Items and Product templates are saved, uploaded back into webmanager and pushed live, you will see the complete list of Related Items no matter which Related Item is clicked on.