Sounds like what you're referring to is known as a comb field in Acrobat (e.g. 1|2|3|4|5|6). You can't create them in InDesign -- they have to be set in Acrobat.
Alternatively, they can be created in InDesign with FormMagic: http://www.id-extras.com/products/formmagic
There is a free edition for shorter form.