Communicate in an open and honest manner. If I suspected a particular tenant of causing the problem, then I would approach them first. Use this as a teachable moment. It's amazing how many people don't realize how to dispose of baby wipes, "personal" wipes, and other paper products appropriately. Provide an appropriate disposal bin. Make sure the issue is covered by your rental agreement terms. It would be difficult to hold them all accountable for the cost of clearing the line and other collateral damage, but I would sure try. If they don't respond to your plea, then raise everyone's rent enough to cover the extra expense you are incurring. They may indeed rise to the occasion, cease and desist.
Here's an excerpt from our rental agreement you may find helpful:
DRAIN STOPPAGES/PLUMBING. As of the date of this Agreement, Landlord warrants that the dwelling’s sewage drains are in good working order and that they will accept the normal household waste for which they were designed. They will not accept things such as flushable wipes, personal wipes, baby wipes, paper diapers, sanitary napkins, tampons, wads of toilet paper, dental floss, balls of hair, paper towels, newspapers, grease, oil, table scraps, bones, clothing, rags, sand, dirt, rocks, or children’s toys. Tenant agrees to pay for clearing the drains of any and all stoppages except those, which the plumber who is called to clear the stoppage will attest to in writing, were caused by defective plumbing, tree roots, or a result of weather. Tenant agrees to keep on hand and properly use a plunger when necessary to unclog drains and to prevent water overflow from toilet, sinks and bathtub. Tenant agrees to notify Landlord in a timely manner of drain stoppages that they are unable to clear themselves.
DRAIN CLEANING PRODUCTS. Tenant agrees not to use caustic drain cleaning chemicals in any of the drains or plumbing fixtures. Such products may cause damage to the plumbing system and may be hazardous to the environment and to people who may come into contact with such product. Tenant may be able to keep drains clean and clear with regular maintenance by pouring down the drain a quarter cup of baking soda followed by a half cup of vinegar. If there is a minor clog in the p-trap (the curved portion) of the pipe under the sink, Tenant may disconnect the pipe, clear the pipe manually, and reconnect the pipe to clear the clog or may call Landlord for assistance.
Give proper notice that you are doing a routine "safety inspection" and see which tenants have a box of those products sitting on their toilet tank.