I would like to recommend PST Merge and Join tool to combine more than two pst files in one. This tool is easy to use for any technical or non-technical user as well as you can use this software to add more than two PST files with relevant mailbox and emails. This simple solution runs on all Windows OS and provides a Unicode PST file for Outlook 2019, 2016, 2013 & other earlier versions. The software also merges the contact, calendar, task, etc. as well so the user doesn't have to worry about the whole mailbox
https://www.osttopstapp.com/pst-merge.html













