Peace options

I've been thinking about it, and i've had a trouble with it recently.

You see, when you are in peace with a certain player, who you need to make peace with in order to secure that he wont attack you without notice (Because you know, i rather have someone behind me declaring me war first and then attacking rather that attacking whenever they want without me expecting it.), this one has access to cross your walls, and thus they can cross your territory even when you don't want them to because they might cross to my cities, declare war and attack them from the inside, and that its really annoying.

But also, you might have peace with another guy that is ok for you to let that one specifically pass through your territories because you know he is not a threat to your nation, but you don't want to ally him either because of whatever reason you may have at the moment.

What about having like, a check box option that can make you decide which player has permition to cross your walls and which player does not? it's so simple.

What do you think guys?

Or maybe just fight instead of having peace with all these players, then you know where you stand.

If you don't want a player to cross your walls then don't make peace, problem solved!