The one I showed you really only works for dried food. There are a few other feeders that feed wet food that keep it refrigerated, some of them hold up to 5 meals I believe.
If you have 3 cats I would sugest getting a BIG feeder, if not maybe 2 if your worried. They come in all sizes and if you just want to go out for a weekend I'm sure they will be well fed.
If you decide to go with the wet cat food feeder that despenses meals - you might want to try it out while you are there - so the cats get the idea, and so you don't have to worry if they'll figure it out or not. You might also have to keep one kitty per room if you are doing the wet feeder - since there will only be 5 portions and if one gets greedy - they could go up and eat the other kitties food. You'd probably have to buy 3 feeders - and that's not cheap!
I'd just go with the dry feeder - 2 or 3 days eatting dry food probably won't hurt them and it would be much easier on you fiancialy and mentally.