Each one is a different size you'll notice. That's why they are separated. Files are grouped if they are identical in attributes. That's what enables you to downld from several hosts for a single downld.

Why are they a different size? Probably due to different bit rate & encoder used. Some might be stereo, some joined-stereo or mono, some might have been encoded using VBR & not CBR, & then ... some might be fake ( T3 Spammers; mp3 Bit-Rates Versus File Sizes.)

It looks to me like you've downlded several versions of the same song.

BTW we'd normally prefer you editing out the artist & title. Otherwise it's proof you're downlding copyright material. And that's in contravention of the forum rules. We don't want to know what you're downlding, just what happens that's all.