There is no special tool, but you can achieve it with multiple calls of burusftp user add
command. See more on this documentation page.
Just export your users (their usernames, hashes and salts) to a shell script and run the script on your Buru SFPT Server machine.
Example of the script:
burusftp user add user1 --password-hash salt-first,0x1055d3e698d289f2af8663725127bd4b,0xa0392fed
burusftp user add user2 --password-hash salt-first,0x1234d3e698d289f2af8abc372127987f,0x88ab0802
...