Separation of duplicates with RANDBETWEEN

It can be rather easily achieved with VBA (probably also with formulas, but then rather not very simple solution :-) ).
Especially if you set just a requirement of a minimum period without duplicate.

Random selection is not (as opposite to general feeling) very equally distributed. Try to make an experiment and toss a dice 6 times.
One would expect, as it is random, all 1,2,3..6 appears once (of course in random order). Or at least one expects it will be quite often.
Nope! Probability of such result will be only around 1.5% (720/6^6)

To try to suggest a proper solution a sample file with sample data (following layout of real one) would be grat help.
So attach a sample workbook. Make sure there is just enough data to demonstrate your need. Include a BEFORE sheet and an AFTER sheet in the workbook if needed to show the process you're trying to complete or automate. Make sure your desired results are shown, mock them up manually if necessary.

Remember to desensitize the data. (or may be song names are not so sensitive? then you could leave real data).

Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.