I created this PTFE bowden splitter for my Bambulab X1 printer so that I could use the AMS and single spools without disconnecting the AMS.
You will need three PC4-M10 connectors. Make sure you get ones where the PTFE tube goes all the way through the connector. These are the ones I used: https://www.amazon.com/gp/product/B07P2XRCC1
Update: I updated the geometry of the model, I added chamfers instead of fillets, and made it print in the vertical orientation. No support is needed, but a brim is probably required, this will depend on how much bed adhesion you have with your setup, but it is easy to remove so I would leave it on. The PTFE tubes slot further in the model, about 67mm, so there is a shorter path in the splitter where the filament is not in the tube. It will attach to the back of the Bambu X1C printer by removing the existing screw at the upper corner and using an M3x16mm screw instead.
The old files are still part of the model just in case anyone likes them better.