you can compare two values in the System condition, and then put something like this for the first value:
( a=1 | (b=2 & c=3) ) ? 1:0
equals
1 (for the second value)
the ? checks if it is true, if so, uses value of 1, otherwise if it is false uses a value of 0.
This value then gets compared with the value you put in the second input box.