Maintain position of diagrams from imported PDFs relative to anchored frames in table rows

My FM document contains hundreds of individual syntax (railroad) diagrams. My process for creating and importing them into FM is as follows:

1. In Visio, create multiple diagrams (10 – 20) per page in Visio.
2. Export .vsdx files as PDFs.
3. In FM, create a multi-row table, and insert an anchored frame into each of them.
4. In each frame, import the PDF by reference, and align it appropriately.
5. Create named destinations for all keyword (shown in blue text) descriptions, which are provided elsewhere in the FM document.
6. Create a hot spot around each keyword and link them to the appropriate named destination.
7. Group the imported file with the keyword hot spot(s) in each table row.

This method works well until I must insert a new diagram between two others in the original Visio page. The PDF created from the new Visio file throws off the alignment of the other diagrams imported into the table rows previously.

I am looking for a method that will maintain the position of the PDF file relative to the anchored frames. I’m open to completely new ideas other than recreating all the diagrams! Also, there is no chance that I’ll create separate files for each diagram!

Note- I had used color views previously to create “invisible” cross-references from keywords to their descriptions. I think that method is better because I don’t have to create all the keyword description named destinations. But, I have the same problem with misalignment using that method too.

Please refer to the diagrams I've attached.

Thanks in advance for your help-

Lauren