Let some post be another's children although they're of different custom post types

[fonemi]

Think like a scenario :

I have two custom post types, one is "Product" and the other is "Video".

Exactly what I want is to add a new "product" as parent post, and add new "video"s as its children. And a permalink should be ​http://my_site_address/my-product/my-video/, and the other ​http://my_site_address/my-product/my-other-video/

[SergeyBiryukov]

Looks like plugin material to me at this point.

Or maybe "Product" should be a custom taxonomy instead, combined with /%category%/%postname%/ permalink structure.

[nacin]

The post type API supports this. You just can't do it using the UI or with our built-in post type rewrites.