Do you not?
Seems like an extremely rigid and inflexible rule, hopefully the club has more tact than that.
We should be concerned with getting the best deal for ourselves, selling to a domestic rival gets taken into account but it is only one factor amongst many. Letting that one factor dictate our transfer policy with Rooney is just amateurish.
If Madrid offer £40million and Chelsea offer £40million then you sell to Madrid, but if Chelsea offer £40million and Madrid offer £20million then you sell to Chelsea IMO.
I doubt they club will mind losing money if someone from abroad makes and offer, Levy did the same thing with Modric.