Consider Using Radio Buttons for Mutually Exclusive Actions:

When a rule sheet is represented this way the rules can often extend way to the right, making it difficult to manage

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In this rule sheet we have chosen to use the checkbox approach to avoid the rule sheet extending way off to the right to accommodate the long values in the actions. However it now allows the possibility that a user may select multiple items in a rule column which may or may not produce the correct answer.

If there was a way to designate the action columns as "Radio Buttons" (mutually exclusive) instead of checkboxes then we could ensure that only one choice can be made in any rule.