Trying to Create a Double Chest

I am trying to make the Beta Chests into their own unique item with extra storage. I have the UI figured out and the single chest has all the proper conditions so far. However, it seems making a proper double chest is next to impossible. I haven't seen anybody do it with MCreator, and I've asked for help in multiple places with no good results.

The original idea I had was to create a single block with the dimensions of two (2x1x1). This would work a bit differently from vanilla double chests, but would be much more simple to work with. However, if I do this I have to click the left side of the chest to open the UI. If that weren't the case I'd be all set. However, people are telling me it is 100% impossible to make that work even though I've seen other mods do it with larger structures.

So if we're going on the assumption that my original idea is impossible, then I'll have to create two blocks, one for each half. I will have to go through a boat load of troubleshooting to make sure you can place double chests beside one another, check which way the original block is facing, figure out how to transfer things from the single chest to the double chest when it's created, and how to "split" the items when half of it is broken. A good chunk of these aren't even possible with the current procedures window.

This is, as you can imagine, ridiculously frustrating and tough to accomplish. Most of the things listed above I wouldn't even have to worry about if my original idea of making it one large, functional block would just work.

So yeah, I'm looking for any kind of solution here. Making a mess of spaghetti code that I can't understand or sort through is not a solution. Honestly I would even take copy-pasting the vanilla chest's code if that's an option, but I would prefer if someone would help me make my original idea happen.