You can easily convert Mac MBOX files to PST using MacUncle MBOX to PST Converter. The tool supports Mac OS Machines.
You can create separate PST per MBOX and split PST file in 500 MB, 1 GB, 2 GB, 3 GB, 4 GB, 5 GB and 10 GB parts.
Confirm default destination path or browse different destination path and click on the Export button.