I don't think there's a way to do this while configuring the script—certainly not while the Specify Field Order for Export dialog is open—but one way you could help yourself would be the following:
1. When you open the Specify Field Order for Export dialog, fields will be listed in the order of their current sort, so use this feature to set the fields up ready for your script.
2 Open Manage Database and sort the fields by Type; this will put all the data fields at the top, in the order Text, Number, Date, Container. If you want to, you can manually alter the order to refine the sort to the order you want, the aim being to group together the fields you want to export.
3. Make a note of the last field you wish to export
4. When you open the Specify Field Order for Export dialog, fields will be listed in the order you created, so it is then a simple matter of moving over the fields you have gathered at the top of the list.
keywords: Thanks, all v. sensible ideas.