Is this collusion or ok?

So in leagues I’ve played in, the only trades I’ve ever vetoed were just clear roster dumps, or trades where money was involved. My friends and I now have two leagues, 1 redraft and 1 dynasty. Two teams are looking to trade in both, with one clearly favored trade winner in each league. Should these types of trades be allowed, or does it present an unfair advantage?

While everyone in the dynasty league is in the redraft league, the redraft league is bigger and has members not in the dynasty league. Anybody’s thoughts are welcome!