Although there are many great senior fitness instructors in this forum (and I’m sure you will get some great advises), I would also recommend for you to contact Guy Andrews. He is the founder of Exercise ETC. and he is very knowledgeable when it comes to seniors. I recently attended one of his workshops where he covered a lot of great information, especially regarding exercises and routines for seniors. You should be able to contact him through his site:
I hope this helps.
Since safety is an issue, it is very hard to do group balance exercises. Do you use a balance pad? I love them, sometimes I double them to make it even harder. How about making an obstacle course that requires them to walk over objects, walk under objects, etc…they can cycle through one at a time. I have a few on my facebook page fortify your frame.
As Shari suggests, having a group of seniors perform balance exercises is a safety challenge for you, the instructor. I agree that using a balance pad is a good idea, as well as developing a walking course that challenges the participant to walk over, under and around various obstacles.
I also agree with Harris that Guy Andrews is an excellent source of information on working with seniors.
you can also get inspiration from Tai Chi style exercises which you can modify to suit your needs. There are many DVDs that provide some examples; I am partial to the ones by Lawrence Biscontini.