Hi Bob
Thanks for reaching out on Lucidchart Community!
First to clarify - are the different drill-downs separate pages or layers in your document? If they are separate pages I would look at creating Master pages with a back button linking to the parent model you want to reference then applying the master page to the applicable drill-downs.
That's the only solution I can come up with. I hope I understood your use case correctly.
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If this recommendation doesn't help your use case could you add some screenshots/gifs to demonstrate what you are trying to accomplish so we can get a better idea? If you would like more one on one support you can reach us using this form. Depending on the situation other members of the community may be able to help if you keep the info on this thread but for security and privacy reasons we do not allow document links to be shared on the community.
For anyone else looking for more information on Hot Spots see this article: Actions (Links) and Hotspots