Use secondary account to download books

[johnlescault]

Is your feature request related to a problem? Please describe.
I'm trying to download Audible Plus books. I have 3 Audible accounts total for my family. My youngest only uses Plus! titles, but I don't like them using the audible app openly. I use Libation to download the full Children category. I have a tampermonkey script that adds all the audible plus titles on its own, so I would like to add to all 3 accounts all the Children books, if one gets the "daily max" switch over to the next

Describe the solution you'd like
When one account is maxed out daily, see if the other account has the title during download.

Describe alternatives you've considered
Install Libation on VMs just to run different instances. Seems lame to have to do that.

Additional context
Thanks for the great work!