Merging Custom Rosters

I want to combine a custom roster I created with another roster I had been working on. As of now you can't merge them, only merge your single roster with the EA Official Online Roster. This was an issue the past few years. Why are we unable to merge our custom rosters together? Does EA have a valid reason for not allowing you to select multiple custom rosters to merge. Otherwise, every single time I find a better Downloaded roster, I have to go through and re-create any players I have created, and re-create any teams that I have created. As well as re-do any player ratings I have tweaked. This seems like a ridiculous thing to not program. Selecting more than 1 custom roster to merge should be a simple task, it should not limit us to 1 custom roster to merge with an updated roster, kind of defeats the purpose of downloading rosters. Any answers from EA, or a patch to fix this would be appreciated, thanks.