Ember add multiple models to router with different endpoints

Question about routes and adapters. I have two different models ‘merchants’ which i get at '/merchants/1234' and 'products tags’ which I get at ‘merchants/1234/product_tags’. There is no links in the JSON in the merchant request to the associated product_tags.

I want both of these models to exist in the router 'Merchants', I get how to add multiple models to the router, but does anyone have a suggestion on how to get the second (product_tags) which is a slightly different URL setup within the adapter?