First, as you read this, you may be asking yourself, "Why?" The reason is due to a political nature (got to love working within large enterprises :) ).
Situation:
There is a repo on github. Let's say /github.com/someorg/demorepo.
I've created my own repo in my own org (i.e. /github.com/myorg/demorepo).
Currently, these two repos are not "attached".
Is there a way that I can tell GitHub that /myorg/demorepo is a fork of /someorg/demorepo so that I can do PRs? (I can't check-in directly to /someorg/demorepo.)
Thanks!