pkgng repository priorities

[Nikolai Lifanov]

Is there any documentation about how to use PKGNG repository priorities?
I heard that these are available.

Currently, I have my repository configurations like this:
1-myrepo.conf
2-anotherrepo.conf
3-someotherthirdpartyrepo.conf

This roughly prefers stuff from what appears first in asciibetical 
order.

I would like to use the official FreeBSD package sets, but to do this, I 
need to always prefer a package from a local repository (WITH_NEW_XORG, 
WITH_KMS) if a package is available in it.

How can I set this kind of preference?

- Nikolai Lifanov