This OpenCart related products by Attribute module will allow you to quickly relate Attributes to each other .
Get related products for OpenCart 3 - CLICK HERE
FEATURES

• Relate one or many to many products at once
  
• Filter products by price range
  
• Relate products by attribute
  
• Relate products by attribute Name
  
• Relate products by attribute Group
  
• Relate products by attribute Value
  
• Relate one or many product Attributes to single or many product Attributes
  
• Delete Related products for given Attributes of main products
  
• - one Attribute to many Attributes Related products
  
• - many Attributes to one Attribute Related products
  
• - one Attribute to one Attribute Related products
  
• - one product to whole Attributes Group Related products
  
• - many to many or one products Related products

DEMO
(This is the full demo. In this product you will have only the Price Range and the Attributes tabs in Advanced view)
http://ggwshop.com/oc23bulkrelatedultimate/admin/
user: demo
pass: demo

Requires vQmod 2.3+
Installs via the Extension Installer
Old modules compatibility fix for OpenCart 2.3 included. So your older modules (for 2.1 for example) will magically start to work again.
Check the Documentation its a 1 minute read and install process I promise :)