How to protect merchants in foreign land in remastered?

I'm playing remastered for the second time only, so merchants are new for me. I haven't played Medieval TW, but I know that has merchants.
So here's my issue: If I don't send an assassin with my merchants to take out approaching merchants, they get bought out. If the merchants are in my region I merge one stack of peasants with them to stand on the resource. I want to keep sending them to Egypt because the money is good, but IDK if I want to keep checking on what's happening there and taking out approaching merchants with my assassin before they buy out mine. It's an extra chore. Do y'all have a better method to deal with this issue? Or do you not bother with merchants at all? Lemme know.