Redmine

Hi,
We have two Redmine instances (both 3.3.0) running on two different servers 1 is running with Postgres and another on MySQL,
We would like to migrate both in postgres instance, however we have many additional trackers in MySQL instance compare to the PG.
Now my query is
- Is it possible to migrate these two instance given the above scenario?
- If yes, Is there any plugin/script which can do it without Data loss?
- Or if anyone can guide me on how I can write such script to import all trackers from MySQL instance without disturbing the existing installation of PG.

Thanks