Triple gauge regulator? You mean a dual body regulator with one HP and two LP gauges I assume?
It is possible to do what you want but personally I think it's a bad idea. Directly on the tank, you only have high pressure through a couple inches of solid brass tubing. If you put the regulators in the fridge you have to run all 600-900+ PSI through several feet of flexible tubing. While there's certainly tubing out there that can handle it, it seems like an unnecessary risk because of the chance of the tubing bursting due to being damaged/cut/defective/etc - 900PSI is a lot of pressure.
The SAFER option is to use a single primary regulator on the tank, set it to like 30-40 PSI, and then you can run a low-pressure hose into the fridge to a pair of secondary regulators to reach your target keg pressures.
And you might also find that by the time you find and buy a suitable high-pressure hose, it might cost you about as much as going with the primary/secondary regulator setup instead, because a hose that's 5+ feet long, flexible, rated to 900PSI, and thick/armored enough to be safe for the task, isn't likely to be very cheap.