How to set next js custom path when user have multitenant

Question

I want to make an application for offering multi tenant. I don’t know the word(multi tenant) is correct. For example, A user have one userId as (hey188) The user can have below 3 paths that used for url as (apple, grape, hotdog.. and so on) The user can have a lot of menu and submenu. so we want to present this path and menu in url. For example,

www.domain.com/apple/buy/buydetail
www.domain.com/grape/buy/buylist
www.domain.com/hotdog/buy/buylist

How to set the path apple/grape/hotdog in Next.js ?

Because apple/grape/hotdog are not page. And apple/grape/hotdog data are called by api. But buydetail/buylist are page.

And we should validate whether the user have correct path when user lend page.

www.domain.com/orange/buy/buylist 

I can not find the way to set this path and router.

Please let me know. Thank you so much!