José
The rules say that only one topic per league is allowed, topics that are used to promote more than one league will be closed.
I have questions: by topic do you mean thread? And if so, surely you mean a league can only be promoted in one thread rather than one thread can not promote multiple leagues. There are many threads that promote multiple leagues but don't use multiple threads to do it which I have been told by other moderators is perfectly fine. If it isn't, I don't see why. It keeps the L&E a lot more organised.
Arguably using another thread to promote
1 other league in a family of leagues is also fine as long as that league isn't also promoted in the original thread. If this isn't okay, I guess it's understandable but it also makes it tougher to promote leagues if you are more of an independent host and also something difficult to properly police too as the host could just change the name of the league.
The problem here is both threads promoted both leagues. Each are replicas of each other, there's no obvious unique need for one thread over the other. IGP doesn't like it when people make multiple threads that could be condensed into one as it could quickly get out of hand and make a mess of the forum. So hopefully now you understand @Brad