There is a product on the market that comes in rolls, like foil and saran, which is the same as the product that the bags are made of, allowing you to tear off as much as you need. If you cannot find it, let me know and I'll check my package at home. Pam spray might help a little.
By the way, tell the congregants the "Rebbe" said to rollup their sleeves and pitch in!
Postscript: Another alternative might be roasting bags. They seel roasting bags for roasts and turkeys for ovens in all the stores. See if they have a very large size and use one of those to line the crock pot. That should probably do the trick if it's large enough. They should be. Let me know.