I'd love to be able to track tandem reads based on either format or language.

For example
Reading the digital version while listening to the audiobook version of the same book. (Sometimes content is the same, sometimes it's different for each format).

Reading the English version of a book while also reading the Spanish version of the same book.
(This is helpful for learning to read in multiple languages.)

Currently, I can only choose 1 version of a book at a time, and have to backlog tandem reads.