Umm, you really can't do it.However you can make a really huge map and control it all with triggers.Of course at one point you will have the same situation again, but that may already be the end of the campaign.
If you don't want to do that you can still choice to give the player the possibility to transfer the information.
You already know how to implement a dialogue system with taunts.You could use a similar way:At the end of one scenario display a message that says the player should type in a number in the chatbox on the beginning of the next szenario.Then in the other scenario you use triggers/ AI-scripts to find out what number the player choose, and then make triggers that influence the scenario design, or seperate the map in pieces and create the units in one of the pieces after the player chose a number.I hopse this is not to confusing...
If one map is to small to do all these things you could use a similar methos, but let one special number trigger an instant win in one scenario, while another one let you play the scenario.In the next one you change the numbers around.
Yes, of course you have to depend on the player that he enters the right number, but you have to depend on the player anyway, for example that he doesn't use cheatcodes.
I know this system is complicated, but it should work.
I'm sorry about my bad English.