Well, you can always insert whatever message you want at any point in your tournament by modifying your layout.
One way to do this is to create a new Cell. Copying a cell near to where you want to put the new one is usually best, in that you'll get all the properties of the copied cell. Set the HTML of the new cell to whatever message you want. Then for the Default Property Group, uncheck the "Display" checkbox, so that the cell doesn't display. Then create a new Property Group, make sure "Display" is checked in the new Property Group, and set the conditions of the Property Group such that it is only used in round 5. This way the cell will only be displayed during round 5.
By doing it this way, you'll always get that message in round 5 for any tournament that uses this layout, which may not be what you want. A better way to do it would be to create a new cell as in the previous example. Don't create a new Property Group for the cell. Instead of placing the text you want to display in the HTML input of the cell, place a token name there (make one up, like <mymessage>). Then, on the Rounds tab, in the same way in which you changed the text displayed for the <breaktext> token, just edit round 5 and create a token <mymessage> with the message you want to display.
A bit complicated but I hope that's comprehensible.