I would only seperate if the smaller ferret becomes obviously withdrawn & off its food, as well as trying to escape from the bigger ones attentions,
Why not have the bigger one out first & tire it out engaging it in loads of play for half an hour or so, then bring the smaller one out first, they drag each other round by the neck, ears, face & head its rough play but normal, they squeel at each other also, thats perfrctly normal
just watch the situation & act accordingly, if the tiny ones obviously distressed then just pop it back in the cage i dont believe in this chuc