Automatic feeder issue... Oone cat eats faster than the other

I rarely have to leave my cats alone but sometimes for 2 or 3 meals it happens. When I just had one cat I left out some high quality dry food in my automatic feeder, and voila. BUT now that I have 2, not only is my feeder not adapted for 2 cats (opening too small), but my 2nd cat eats VERY slow whereas my first one eats in a matter of seconds.

I am at loss at what to do when I need to leave them for a day or two, and they cannot be separated as they are very bonded and would go crazy alone. 

Does anyone have any advice or/and know of a good automatic kibble feeder suitable for 2 cats? Thanks in advance. 

I can always book a pet sitter or ask someone to come but I'd rather not have to worry about organizing everything in advance every time I have to leave. 

I have seen feeders on zooplus.co.uk that are controlled by the cats individual microchip, so you could have one of those to put some additional food for your slow eater. He would be able to eat when he feels like it- the flap will close as he moves away. This would stop the fast eater eating all of his food! However they open when the cat is near rather than at a particular time. They are also very expensive!

Thanks for your reply! I've seen these but unofrtunately I'm pretty sure my slow eater won't instinctively go near the feeder if it's closed. Plus as soon as he is close enough my other one will definitely rush to steal the food.