Closed aplha testing on google play store

I have many dev teams working on multiple features in my app on separate branches. I also have other dev teams working on beta test version in parallel. I haven't used the Google Play Store testing tracks except beta and want to know more about the closed alpha tracks. I did read up on the Google developer help but i think my doubts were not solved. Putting them down below:

1. Is it possible to publish to alpha and beta tracks simultaneously? For example - usually, in my team there are 2 different version of the apha build as they are being worked upon in parallel by two different groups and a single beta version which is more stable and being tested by a larger group. Is it possible to release these three builds to two apha tracks and one beta track?
2. What will happen to the beta build If i upload a build to alpha track? Are they independent? Will beta testers see a different version of the app if i upload a build to any of the alpha tracks? Or will these three tracks be separate and maintain their own versions?
3. Is it possible for a tester to be added to multiple testing tracks? Or be added to multiple tracks of the same type?(e.g - adding the same email id to both the alpha tracks or adding the gmail id to all the 3 testing tracks).
4. If point 3 is possible, what will happen if i release build to multiple tracks? Will all the builds be visible to the person? How exactly will he/she download the builds from different tracks?

Any help appreciated. Am trying to setup a managed process to accelerate app testing and feedback within the team so that we can have faster iterations

Thanks for the help in advance

Kartikeya