There is an Archive Manager Edition of RME which is free to current Archive Manager users that allows you to connect to Archive Manager as a Source and Target and Import or Export PST's and other formats
Below is a link to a Video that shows you how to import items into Archive Manager using Recovery Manager for Exchange
https://support.quest.com/archive-manager/kb/93846
Below is a KB article that explains how to get a Archive Manager edition of Recovery Manager for Exchange for free.
https://support.quest.com/archive-manager/kb/134434