Hi there. I am not a hunter and will let them figure this out, but I think they will need to know the guns (especially chokes) that everyone has. I am guessing that your 1100 has a fixed choke, probably a fixed full choke, that is not rated for steel.
Will your buds be shooting guns rated for steel?
This recent thread may be of some help and I assume that you don't want to get a new barrel or have screw in choke tubes installed. Look at the posts by Virginian-in-LA and Big Pard.
http://thefiringline.com/forums/showthread.php?t=505014