I believe what you're thinking of is a version of this...
Male quick disconnect fitting going to the Performer tank. And on the other end a female connector for the 20# tank.
I've never looked for one, but I'm assuming you'll need to build one.
I would use a short hose between the fittings to give you some flexibility.
Then, would it work the same as filling the small one pounders - I wonder.
Let us know if you do it.
I found the propane guy near me just fills them (someone else just typed that)
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