What is the best way to mount seven flats as a "Backdrop" type wall if you will?  I am directing a holiday show, and would like to use these flats as a wall to project different color lights on to signify different places, as our theater doesn't have fly space to use multiple sets or drops.  How would I mount these flats so that they are secure and safe.  This is a childrens production and if I injure anyone, I probably won't be invited back!  Any advice you can give would be appreciated.