If you feel he is hurting the girls, give separating him a try, see if the girls seem much more relaxed.If I seperate him for a few weeks in a pen next to the girls where everyone can see each other, will there still be the need to reintegrate him?
Adding him back once the girls are all laying will probably be a bit harrowing at first, but hopefully they will submit and he'll calm down pretty quick.
How much space do you have?
Is he keeping them from eating and drinking?
Are there places for the girls to get away from him?
Places 'out of line of sight'(but not a dead end trap) and/or up and away from any bully birds. Roosts, pallets or boards leaned up against walls or up on concrete blocks, old chairs tables, branches, logs, stumps out in the run can really help. Lots of diversion and places to 'hide' instead of bare wide open run.