Is it possible to 'quit' section in circle.yml under certain conditions?

I’d like to have the ability to quit section in case some condition occurs.
For example:

    - echo A
    - echo B
    - if [ $SOME_VAR = 'X' ]; then --- end override section ---; fi
    - echo C
    - echo D

The meaning is that if SOME_VAR is defined as X, the commands echo C and echo D won’t run.
Is it possible? Or do I need to use the - > notion in order to implement the condition in a single command?