This is called a conditional value list. Check out the Forum tutorial in the links listed below. With your specific case, Option 1 may be a valid shortcut over the more typical relationship based conditional value list.
Forum Tutorial: Custom Value List?
Knowledgebase article: http://help.filemaker.com/app/answers/detail/a_id/5833/kw/conditional%20value%20list
Hierarchical Conditional Value lists: Conditional Value List Question