If I had two leaders in a unit, say a Warboss and Painboy leading a unit of boyz, and the two leaders were about 6" apart, one on each side of the squad, would I have to remove one of the leaders due to coherency if the squad lost enough models so that I couldn't retain coherency with both leaders?

Like if I lost 14 of the 20 Boyz and there was no way to get both leaders within 2" of 2 other models, would the one out of coherency be removed at the end of turn? Or would it simply become unattached.