Use @CHILDREN or @DESCENDANTS to set values

@CHILDREN

I have some IF statements based on an "Activity Plan".  Instead of listing all entities in each IF statement, I would like to use @CHILDREN or @DESCENDANTS so when my Entity list changes, I don't have to make the changes in my calc scrips.What I have

IF("Activity Plan" == "Boston (Activity Plan)")

"Boston Assurance" = 1;

"Boston IT" = 1;

...

ENDIF 

What I would like to do:

IF("Activity Plan" == "Boston (Activity Plan)")

@CHILDREN("Boston") = 1;

ENDIF 

Or something to that effect.  Is there something I am missing on doing this?  It doesn't validate, it just says that there is an error please look at line:## and Column:##