You can try to take a look at the official level 1 of the hammerwatch campaign for an example, but essentially each exit is going to have 2 numbers, 1 is the number of the level its going to (in your case its the same level) and the second/startID is the ID of the 'level start' script that you place as their spawn point.
On top of this you have to edit your levels.xml to include all the levels in your campaign/act.
So lets assume your level is level 1. Then for your LevelExitArea it should be new level: 1 and then since the default LevelStart id is 0, you place another 'levelstart' script at the point you want them to appear when they use that exit. Change the ID of that levlestart to 1,2,3,4, whatever. And on the level exit area you would change the LevelStart to the # of the LevelStart you want them to appear to.
Every time I write this out it seems more complicated than it is, but try to use the Level 1 and 2 from the HW campaign as examples it may help. Let me know if you need any help, and if you want to send me your xml I can fiddle with it for you.