Trying to find the nearest profession trainer, for a specific profession

[pbettell]

So I know I can use

Styx.Database.NpcQueries.GetNearestNpc(Styx.WoWInternals.WoWFactionTemplate, uint, Styx.Logic.Pathing.WoWPoint, Styx.UnitNPCFlags)

To return the nearest npc, but within UnitNPCFlags, I can't seem to get anymore specific than "ProfessionTrainer"

I'm trying to write a plugin that trains Skinning/Herbalism/Mining automatically, but can't send it to the right trainer.