Any notion of file affinity in XFS?

[Jean Francois Martinez <jfm2@xxxxxxxxxxxxxxxx>]

I see many cases where for performance reasons I would like being able
to tell XFS that two files should be physically close (affine) so disk
space allcation should treat them as a whole.  It could be something
like that:

-tell the filesystem that the files I will create are affine
-create them
-revoke affinity.

Does this exist?
-Any plans to implement it or know of a filesystem where this exists?

                        JFM