Merge multiple mail accounts into one in outlook 365

Bought a new PC and installed office 365 on it. All is good except an outlook issue.

I have 3 different gmail addresses. Now in out look, I get 3 sets of folders for each - as an example, I have 3 inboxes for each of them. On my old computer I had only one Inbox and all mail from 3 accounts went into it.

In outlook, when I go to File->Account settings->Account settings->email, all three accounts are there but at the bottom where there is an option to "change folder" button, this is greyed out. Hence I cannot change the location of inbox to one pst file. Help please.

bro67 said:

Quickly merge or combine Inbox folders of multiple accounts in Outlook

Thanks but this does not work with IMAP accounts which Office365 seems t create.