Custom JSON renderer for pages created with a specific template

[Former Community Member]

I have a requirement to generate a custom json for the pages created using a specific template. My implementation should not break the default *.json for the pages created using other templates.
I had found an option of creating the "resourceType" based servlets with "json" extension. But it expects the pages to be rendered as *{pagepath}/jcr:content.json. I want the end user to still hit these pages as */index.json and not as */index/jcr:contnet.json