Is it possible to batch process the website url for all 50 songs in playlist at once. Sort of tedious to link each song individually.

Sadly no, but you can put the link the playlist description instead. Just use the link button that's next to the Bold and Italics buttons when you enter your description.

Also, I've noticed a lot of users just link the first song in the list if the link applies to them all.

Thanks EricJ