Arris Windrun
Gutter Goddess
DIPLOMACY
The Sith Covenant does not maintain a central government. There is no foreign office or foreign policy.
If you, as a nation, government, corporation, or other entity wish to be in "good standing" with the Sith Covenant, then your best bet is to be on good terms with at least one Triumvir, if not all the Triumvirs, if not the majority of the Sith that make up the Covenant.
Otherwise, you are most likely considered anything from 'fair game' at worst to 'not in consideration' at best.