Selecting only the songs I do not have locally in a playlist?

[DeltaSt0rm]

Hi everyone,

So I had 13,000 songs on my old laptop (Windows) which I used to listen to through Spotify in a Local Files playlist. Now, after purchasing a new laptop (Mac), I want to transfer only the songs that Spotify does not have so I can continue to listen to the same music but the majority through the online Spotify versions and the minority as the local files that I have put onto this new machine. 

Does anyone have any idea how I might do that?

Thanks a lot!