V.L.
Hang in there, R..
Being consistant with the Youth club and Church youth programs will help since kids need to hear behavior requirements from other adults in order to validate what you have to say. It's tough particularly with boys with that old phrase "boys will be boys" being thrown around like it is. (I have two boys and my youngest has even quoted it before!)
They are at a tough age, carving out their place in the world and trying to be their own "man", so just keep up the instruction and spending time with them individually so they have the opportunity to discuss their frustrations and joys with you and without interruption.
I do make sure to compliment the boys when they do something right. I suggest you tell them out of earshot something like, "Wow, I am sure proud of you for not pushing your brother like you could have - you are really showing maturity when he was so rude." You don't want to encourage jealousy, which could distract from the power of your compliment.
I saw some payoff last week - some girls were throwing rocks at my youngest from the school yard across the street, and there were two boys with them chuckling. My older son saw the goings-on, and paced around beside his kid brother with a tough glare and posture until the other four kids backed off. I do wish he hadn't thrown a rock back, and I told him that was too much. He said he can say anything he wants to his brother, but noone else can.
I like how you mention the bahavior to the girls, since they might be tempted to do the same. Better now than later. I'd suggest you make compliments on their behavior to each other, too. (Again, out of earshot of the others so there isn't any reason for jealousy to distract from the power of your compliment.)