Can't create trade route 1.1.1

Why is it that if a faction has created a trade route between their home planet and mine, i.e. they are the originator of the route, then I can't create a trade route from my home planet to theirs?  It tells me that there is already a trade route between those two factions.  But they are getting the extra benefit of being the originator of the first, and I want the benefit of being the originator of the second.  Sure, they're between the same two planets, but it would be just a little bit of extra code to keep track of who the originator was, wouldn't it?