Mananing standing with non-standard factions

[Zax]

Hello,

How could I manage specials factions reputation, those which standing name or reputations not handled by FACTION_STANDING_LABEL, as described here:
https://wowpedia.fandom.com/wiki/StandingId

I currently use GetFactionInfo() to retreive factions standing but results are very strange with non-standard factions.

Thank you.