I was using a bowden tube/cable holder and wanted to add a y- splitter to make using the external dry box a little easier. I was unclipping a tube to add the external box's tube to the AMS. I crafted this solution in TInkerCad and really like the snug fit.

The bowden tubes and power cable fit securely in place. The cut bowden tube pieces push snuggly into each end of the y-splitter. The finished piece is a single clean solution for what I needed. If it is something that will solve your needs too, give it a try. If there are some issues or tweaks, let me know and I'll see what I can do. 

I have found that a couple times, the bowden tube leading to the adapter has slipped out and caused AMS to fail to load the filament. I have shoved the tube back in to the adapter and it continued to work fine. It has onlyhappened twice and I think moving the rubber sleeve thing closer to the adapter to help maintain the connection helps, but without resorting to glue, or positive locks like on bowden tube connectors, it may be an intrinsic fault of this type of connector. 

Directions:

***Determine the direction you want the external filament access to come from***

• The Pooper-Side model is designed with the feed coming from the non-screen side of the printer
•  The Camera-Side model is reversed from my set-up, with the feed coming from the screen side

1. Now that you know which direction you want, print the part with the settings in the profile. The .10 layer height will take a bit longer, but it helps to make sure there are no y-splitter clogs.
2. Inspect the printed part. Make sure all the path ways in the y-spitter are clear before you begin. I haven't had an issue in the few that I've printed, but I'm using dry PLA Pro filament. Clearing a stray strand or two now will save you a headache later. Run a scrap piece of filament down through both ports to make sure there are no major obstructions. 

3. Make sure you are willing to go through with the procedure. If you have 5-10cm or so of PTFE tube, possibly sourced from the bowden tube you will be feeding the splitter from your external source, you will not have to cut the existing Bowden tube. If not, you will have to cut one of your existing bowden tubes. If you decide after the fact that this wasn't what you wanted, there are bowden tube connectors on MakerWorld to ‘reverse’ the cut, but you might also need to purchase a new tube.

    

4. If the printed part seems good to go, procede to step 5.

    

5. If you have an extra piece of PTFE tube sourced from elsewhere, disconnect the bowden tube you want to feed the external filament through from the AMS lite Filament Hub and push it into the into the nearest-to-center part of the y-splitter. Press firmly to make sure it is fully seated. Is should be a tight enough fit that no glue or anything is necessary. Firmly insert your separately sourced 5-10cm of PTFE tubing into the bottom of the y-splitter, and insert the bottom of that piece into the AMS lite Filament Hub. Viola! 

   If you are using the existing Bowden tube,  retract the filament in the bowden tube on the front side of the hub that you want the external filament to feed from, and with a sharp razor-type blade, try to make a square cut, about 8cm from top of AMS lite Filament Hub. Insert the hanging side of the cut bowden tube into the nearest-to-center part of the y-splitter. Press firmly to make sure it is fully seated. Is should be a tight enough fit that no glue or anything is necessary. Insert the top of the remaining bottom piece firmly into the bottom of the y-splitter portion. Same deal here, press firmly to ensure it is fully seated.

    

6. snap the remaining three bowden tubes into the long slots of the holder print. These are a tight fit, but they should fit. 
7. Connect the extended arm to the power cable in a natural location along its length. See picture.

8. Marvel at the clean elegant beauty of the design. 

    

   For normal operation of the AMS Lite, you shouldn't have to do anything different. It should retract and push through the connector without any issues. When you want to use the external filament, retract the filament in that tube before the connector, and insert your external filament choice into the open port when prompted by the printer. 

Popleta's version:  as a request, I created a longer armed version (45mm). 

I have also found that if you carefully heat up the arm, like with a lighter, you can twist it and hold till it cools for an angled hold: