How to create Kendra sub-index for mutti-tenancy

I watched this YouTube video on Amazon Kendra. I am interested in creating a search feature for our SaaS application. https://www.youtube.com/watch?v=aJ0HUTGs3XY&t=2177s

In the video the presenter explains how you can create sub-index for your clients. This will allow you to have only one index but separate suggested queries and other things like that. Now I cannot find any documentation on creating a sub-index in AWS Kendra.

I am wondering if this video was trying to explain something in less technical terms.

Is creating a sub-index just using Kendra's ACLs and passing user context into each query? Or is there an actual way create sub-indices for each client?