There may be instances when you want to use the same bookmark name more than once in a Bookmark Template. You may have two or more tables, each needing the RR_DocItem_Description bookmark, or you may want to reference the Project ID in more than one place.
Since bookmark names must be unique to a template, you can add a user-defined fourth segment to your bookmark name. These additional segments can be thought of as extensions to the prefix because they are placed between the prefix and the alias_fieldname (ex: prefix_prefixextension_alias_fieldname)
The prefix extension serves both to identify the bookmark name and to distinguish it from other instances of the same bookmark. For example, if you needed to use RR_DocItem_Description twice in your template, you could use the following bookmark names: RR_First_DocItem_Description, RR_Second_DocItem_Description. Shorter prefix extensions are preferable, so you may want to substitute a single letter for “first” and “second” RR_A_DocItem_Description and RR_B_DocItem_Description.
While prefix extensions are often used with the RR_ and RC_ prefix, they can be used with other prefixes also.
Since the numbering prefix extension must follow a prefix, use FG to apply default format, for example FG_1_DocHeader_DocNo