Have a look at this add-on:

https://addons.thunderbird.net/en-US/thunderbird/addon/get-selected-mails/

It allows you to group your accounts by category. I use it pretty much in the way you seem to be describing, to keep personal and work accounts separate.

There is also an add-on that allows for grouping accounts by color:

https://addons.thunderbird.net/en-us/thunderbird/addon/account-colors/

Zenos said

Have a look at this add-on: https://addons.thunderbird.net/en-US/thunderbird/addon/get-selected-mails/ It allows you to group your accounts by category. I use it pretty much in the way you seem to be describing, to keep personal and work accounts separate.

Sadly it does not create the account groups in the visible screen. Only gets email for a select group of email accounts. Postbox has account groups which make it so easy to group email accounts. Like Work, Personal, Project 1, Project ..x. I wish thunderbird had as it seems simple enough

sfhowes said

There is also an add-on that allows for grouping accounts by color: https://addons.thunderbird.net/en-us/thunderbird/addon/account-colors/

Yes this is a good work around. But would be good to collapse groups like a thread. Thank you for your suggestion though.

Maybe you would benefit by using Saved Searches to group accounts, or create multiple profiles managed by ProfileSwitcher.

Is there a solution to collapse groups of chosen inbox account like a thread. Like postbox does so we can have account groups like Personal, Work, Projects etc. Will anyone try to code this? or addon? PLEASE!

Postbox is based on TB code, so it likely uses Saved Searches to display account groups.

Thank you .. so is there a solution you could help me with? Many thanks in advance.

The instructions are given above in the Saved Search article. Start from File/New/Saved Search and Choose... the Inbox folders for the accounts you wish to view as a group. Create Saved Searches named Personal, Work, Projects etc.