Split PST File into multiple small PST files, you can use the best Split PST file software. This tool provides multiple options to split PST files such as Split by A straightforward program to split by size, year & folder PST is one of the most widely used platforms for MS Outlook for Windows. PST holds a number of databases.you can download the free trial version which converts few items from each folder.you can download this tool from here:-Split PST File - Freeware Service to Split Outlook PST Database
For this specific issue, you can use a PST Splitter Tool. It is a software application that allows you to add PST files regardless of the size of the file. This utility splits files by size, folder, date, etc in the least amount of time. It is quick and has customer-oriented features such as an easy to use GUI. It operates optimally with all the versions of MS Outlook and Windows OS.
To analyze the tool in detail, try out its free trial run, here:- Split PST file