Song Battles

I am currently deployed and have a few missions while I am gone. One being writing songs. The last time I was deployed that was no problem and I figured it would be the same this time. Well its not. This time I need to write songs for 2 groups with different styles. Why 2 groups? Well I decided to help a good friend of mine start another group. So now I need to write songs for Joyful Noise and for the new all men's group Reach. I'm not sure how to do it. How do you write in 2 different styles? The only way I can think to do it is to write one and see who likes it the most. Any suggestions?