Clovis wrote:that's the only variable at my disposal, the current event system cannot store a sum created by several events
It could be done, but it would be a lot of work; probably more work than it is worth.
Event1 fires. (no description or effects necessary, just a tracking event)
Event2 may fire if Event1 has already fired.
Event3 may fire if Event2 has already fired.
You can have as many of these as you need.
The conditional event that has effects would look to see where you were in the progression.
It could be made more sophisticated, and add in events for a reverse progression, but that's the basic premise.