Pooping on the guest bed

[Lost_in_MD]

One of my four cats has recently started pooping on the guest bed and if that door is shut goes into my son's bedroom on one of his stuffed animals.  We thought we had the culprits isolated and were working it up for a medical condition (the two isolated have GI and arthritis issues) but now it has become apparent that it is one of the other two younger kitties.  From what I can figure it is because we have had a ton of guests recently staying there because I am on bedrest.  They are all guests they are fond of, no strangers.  Whenever the guests leave, so does the poop.  If it was as simple as locking the door at all times, I would do that but the moving into my son's room is unacceptable.  There are no new pets, new environments, new food and the new baby isn't here yet.  The remaining two are free of medical conditions.  This appears to be pure anger at the guests staying in that room which was infrequent in the past.

Any ideas before I have to put my animals down?  They are literally pooping on the person while they sleep sometimes!  And if they are locked out of my son's room and the guest room at night, they sneak in when the guests leave in the morning while they are moving bags etc...literally in minutes.

[Savas]

Took care of the double post for you;

Make sure you clean up the mess using a product like "nature's miracle". These messes leave behind trace odors that normal household cleaners will NOT remove. Thus; your cat still smells the odor after normal cleaning.

I would suggest (temporarily) try putting a litter box in the guest room/son's room. The idea would be to determine if this is a stress issue between the cats over use of the original litter box, or a behavioral acting out issue aimed specifically at the humans in the household.

[Lost_in_MD]

Oppps, sorry, ignore this post, I can't seem to delete the duplicate question.  I'm very sorry.