This is what you would need to do in order to do what you want in your example there. I'm using the Agema Hellenikon in my example, because the Agema Hellenikon are fucking epic.

recruit "eastern infantry agema hellenikon" 0 requires factions { pontus, } and hidden_resource NW and hidden_resource C and hidden_resource y1 and hidden_resource n2 and hidden_resource y4 and hidden_resource y8

recruit "eastern infantry agema hellenikon" 0 requires factions { pontus, } and hidden_resource NW and hidden_resource D and hidden_resource y1 and hidden_resource n2 and hidden_resource n4 and hidden_resource n8

Insert those lines into the corrrect barrack entry*or entries* for a faction in the EDB and now the Saka could recruit Agema Hellenikon in Gawjam~Kimbrioz and Gawjam~Skandzawarjoz.