Well, that’s just my opinion; I really don’t know shit.
You could try training, but I can’t guess how successful you’d be.
I’d start with treats and “leave it.”
Hold the treat out. Let dog sniff. Say leave it. Don’t let dog have treat unless it looks away/loses interest. Practice until he’s good at that.
Toss treat at dog’s feet. Say leave it. Praise if he does. Ignore if he doesn’t.
(This has been working out with my dog. She picks shit up on walks. It’s gotten so I can just glance down, say “leave it!” and she drops it. I had to pry a lot of shit out of her mouth before she learned that means ‘don’t eat whatever you’re eating.’)
Then, when the dog can stand there, in a sit-stay, for say, a minute while his $10 million dollar favorite treat is right there in front of him, then he’s ready for a guinea pig meet-and-greet. Put guinea pig cage on floor, let dog sniff. Say leave it. Pick up cage. Rinse, repeat.
Work your way up to: put dog in sit-stay. Go get guinea pig. If dog is still in sit-stay, let him sniff Guinea. Say leave it.
You repeat that “leave it” command every time you want him to leave something alone that he wants. You can teach a dog to ignore a piece of cheese, so maybe you can teach your dog to ignore the guinea pig. Think slow progress, baby steps, and make sure you can voice-control the dog in a sit-stay first. When the dog won’t break sit-stay without your permission, he’ll get leave it. If you get that far, then you can probably make the dog sit-stay and leave it, but I’m not sure if you’ll ever be able to let them all just roam around the kitchen together, freely.