It will probally involve several details.
1- the players level will be based on a QV.
2- He will then deploy a unit in QV Area.
3- Then the camera will move to the unit.
4- these ares will have other units.
5- If a certain unit is seem it loads a scenario.
Next what happens is you make X versions of the next scenario. all the same however each starts with the player level moved forward however much is needed.
So for example.
Player 1 finished the first map at Level 11.
a unit is deployed in space 11
the camera moves to space 11
another unit in allready in space 11 is seen
this loads scenario 2 variation 11.
Its easyer for the player in game but requires ALOT larger downloads and a bit more work from the dessigner.
Personally i would use the code system.
Out Reach
The guy who writes the erotic fan fiction in Yeebaagoon's signature