You can merge the current symbols into an existing include file. Older Windows programs may put include information from various sources in the same file.
However, your development effort will be most trouble-free if you follow the Dialog Editor's default and use the same base name for all three files that the editor writes. This encapsulates your dialogs into three easily identifiable files. If you later want to archive your dialogs, examine them, or export them to another environment, your job will be easy.
For information on including files in your application, see “Including New Dialogs in an Application” on page 13.