Marilyn, just as an FYI, there have been quite a few debates here on TCS about the use of laser toys. While many feel as you have described, as someone who lives in a really rural area and has both indoor (all rescued ferals) cats and works with/rescues/TNRs outdoor feral cats, there are many, many times kitties encounter bugs and are never able to catch them. In my opinion, just something to consider, the laser mimics this action, and can give much needed exercise to indoor kitties or overweight cats.
However, because of the frustration that can/might be/is involved in using the laser, one of our most respected and long time members recommends putting a treat under handkerchief and making the "laser game" end there. It is then a fun and satisfying way to end a great play session with a laser.
The advice to separate the kitties for "alone" play time is great. We never had the problem of one kitty attacking another during play, but as we had younger kittens with older cats at various times, we did have a problem with "play" hogs.
We made sure to give each cat 10 - 15 minutes of alone time play each day (just take them into a room with a door!).