Jason,
number one, real friends shouldnt ever put you in a position that would make you uncomfortable, at the same time, it is good to be aware of the nature of your friends. That way you can make eduacated choices about hanging out with them or not. I know this is easier said than done, but wipe your hands clean. I tried my best to get certain friends of mine to change as well, and they never did. Drugs, cheating, you name it, some of them did it. It was very hard, many of them accused me of not caring about them anymore, or judging them. Even to this day I don’t love them any less, but I can’t be around them because of their destructive behavior. Maybe it is selfish, but it hurts me to watch them hurt themselves, so I cant be around it. Make stronger connections with those friends who do share your moral standards, things like this aren’t ever easy. Only God can truly change these people, but first they have to personally want that change and then ask for it. If they are true friends anyway, they should understand your positon. They too can always change, I am not saying to have false hope, but that there is always that possiblity.