Making New League Structure Problems

Hi Folks. 

I'm currently trying to make the Scottish leagues to how they plan to be in the next couple of years. East of Scotland Conferences will split into a division 1 and two. Same with the West of Scotland Conferences. I have also added in a North of Scotland League which takes teams from the North and Tayside junior league to form a feeder league below the Highland League. My issue is that the teams won't stay in the divisions after the first year. I am able to get the correct teams (top 8 Tayside, top 8 North juniors) and they will play one season then disappear to different leagues, leaving the league bare of any teams. I'm stumped as to what the issue is. Any ideas? 

Cheers