Lannister and Bannerman

[Damocles17]

When playing a commander that requires specific counts as such house does Mountains men count as Lannisters or clegane? Then if you add roose Bolton to them are they now counts as multiple house units or now Bolton.

 

[AutumnLeaves]

All units in the Lannister faction are Lannister units
"House Clegane Mountain's Men" are both a Clegane and Lannister unit.
If Roose Bolton is leading them, they are a Clegane, a Bolton and a Lannister unit.