Hello from the USA
Wow you have six we started with five and that was a handful. You literally have to treat them like 5-year-old kids anything they can get into they will. My first suggestion to you is make a list of all the things your piggies definitely should not eat.
Foods Guinea Pigs Should Never Eat - Oxbow Animal Health
From what I understand paper, toilet paper and paper towel rolls would be fine just nothing with glue. I would have to say any other kind of animal food will be very bad because these are herbivores and their diet is very different than a dog which is a carnivore.
I'm only posting the picture of the Sherwood appetite restore because of what it says on the back of the packet. I found this to be extremely helpful bringing one of our sick piggies back to health.
If you train OMG all 6 of them properly you won't have too much troubles but what I found is they have very short attention spans and memories so it's literally an endless process. Lol
Take care
Brian