You can "compare two values" at the top of the list in "System" You can then put two formulas in the fields like that.
https://www.scirra.com/manual/124/system-conditions
Or if one is a global variable, you can compare variable. If it's an instance variable in a sprite, then you will find that option under the object, rather than in System.
That's how I do the levels, I've even use the same names.
it works?i can't use that,if i write it,it always says "There's no Expression like that"