I can see where you're coming from Diane, I have the same issue. I would think it is something that a lot of websites have to deal with it. I will give you example from one of my own websites, not sure if this will help or not, but it's how I deal with the problem.
On my travel website, I have lots of pages that fall into the class of "multiple parent". The old local Brewery for example. Now, this is part of the historical Chaffey trail which has about 9 points of interest on it, all sites of some historical significance. So of course it is a T3 of that section. BUT, it is also something that should appear as T3 for my local wineries and breweries section. AND it also houses a museum of early brewing equipment, and I have a local museums T2.
So that is at least 3 "parent" pages, but I certainly don't want to have 3 sets of breadcrumbs. That helps nobody and does nothing but clutter up the page with confusing info. The thing for me to remember, is that the vast majority of people will arrive at that page from the search engines. So where they came from on the website previously is a moot point, they didn't come from anywhere.
And for those people, a "related pages" group of thumbnails is more than enough... one to see More pages about the Historical Chaffey trail, another for the wineries and breweries, and another to see more museums. I could also add in a 4th, with things to do or whatever.
When I create my breadcrumbs, it all happens automatically, the link in that will be whatever parent I choose for the page (using wordpress) So the breadcrumbs will show something like... home > Chaffey Trail > Old Brewery and if they did in fact come from there, then great. If not, no big deal IMO, the visitor can either click the back button, or choose a related page thumbnail from the bottom.
So really, it's nothing I will lose any sleep over, if somebody doesn't see their originating T2 page in the breadcrumb trail. I don't suppose they will be too concerned about it either. The parent page I choose for these type of pages is the one I expect most people will follow a T3 from, and the one that makes the most sense.
I think you should also consider what is called "content siloing" If you have never heard of that term, it means to have each section of the website distinct and separate from the others, without having excessive
cross linking across those sections. It's a fairly well known technique, and should help Google with getting a clearer picture of the site hierarchy.
This website gives explanation and examples of this. https://www.web-savvy-marketing.com/201 ... tent-silo/
They use Barnes and Noble as their example, which of course has an untold number of books for sale, and naturally there could be huge crossover if they wanted to do breadcrumbs the way you are hoping to do it. A book could be a western, it could be fiction, it could be by a particular author etc etc etc. Think how unmanageable breadcrumbs could get if they tried to have a trail back to every possible parent page?