You've gotta love how nobody actually answered @Liberty.In 's question.
He's asking if there are any trade routes within the House of Gallia only. - Not from Gallia, not to Gallia. WITHIN, meaning point A starts in Gallia, point B ends in Gallia.
I personally don't know by the way. I just wanted to point this out since it irritated me that a clear answer was seemingly evaded.
When contending with a monster, you'd be wise to give the devil his due.
