I have several webmail accounts tied to a single inbox in Outlook

One of my 2 gmail accounts started pinging me for the password, but when I typed it in, it failed to go through and the annoying password window kept reappearing until I "x"d out of it or hit cancel. This has happened in the past with gmail accounts.

To correct the problem, I just deleted and reinstalled the gmail account in Outlook, following the IMAP instructions. It has worked in the past.

Now I have my main inbox which has 4 webmail accounts and all the incoming messages are integrated into a single inbox. That is what I want. The problem is the newly re-installed gmail inbox sits as its own separate inbox down by my personal folders. I don't want that. I would like it combined with my other webmail accounts.

How do I do this?

Bonus points for why does my gmail password "go bad" after a couple years, requiring me to re-install the account? It appears to only happen with gmail. Is there a better way to correct it, short of re-installing the account?