http://www.catchingcamp.comHe has a good video on training catchers
Like stated, keep them busy, do different stations such as T, soft toss, rapid fire drills, pop ups, infield drills. Run each station 10-15 minutes and rotate. Have 3-4 girls at each station. Then maybe some situational practice at the end. Theres quite a few sites to get drills from
If you dont have coaches, recruit some parents and spend a couple minutes showing them the drill and how you want it done, what would be wrong etc.
You will probably find the girls need work at all levels and all you can do is chip away at it and teach them. Just remember its rec and you are there to teach them