If I understand your situation correctly, there’s no need to link your described supporting table to your data model. Sounds like a textbook dynamic segmentation problem that Sam has addressed in a number of videos. Here are just a couple that should be directly relevant and very helpful:
https://forum.enterprisedna.co/t/grouping-segmenting-your-data-with-dax-measure-logic/588
https://forum.enterprisedna.co/t/detailed-banding-segmenting-example-in-power-bi-using-dax/584
If you have any problems after taking a look at these please just post your PBIX file and I’ll be glad to work through the issues with you.
- Brian