Calibre and Sumatra portable interaction

Hi, It's been a long time since my last post here but I'm still an active PApps user.
Question is as follows, I have a Calibre Portable installation in a USB drive wihtout anything else. Just the App and the library with dafault settings. This app is storing 1000 PDFs which are scientific papers about a specific subject. The intention is to allow colleagues to copy the USB drive so they can have the collection with them. I renamed the CalibrePortable.exe to something like ScientificJournals.exe and that's the only think I changed in that USB.
The think is that when I open a file it opens in the default PDF app of the host computer. What I want to do is to also store a Portable PDF reader, let's say Sumatra and when someone click on a file it makes it open in the portable PDF reader.
I know that somewhere here there was a registry default app portable redirector (eXpresso and/or C.A.F.E.) that I used to automatically load when using PApps but that was about 10 years ago and in this specific case I'm not running the App from the PApp menú as usual so I need a different solution.
What can I do to make a Portable PDF reader the default PDF reader of portable calibre both in the same USB?