Document submission on behalf of primary visa holder

Hello everyone,
Me and my wife’s visa document submission appointment is on 20th of this month. Can I visit the consulate and submit the documents on behalf of both of us( Wife is the primary H1B holder) or the primary visa holders presence is required? If I am allowed to submit the documents then do I need to carry any consent letter from her? Please help

You can submit on behalf of your family.

http://cdn.ustraveldocs.com/in/in-gen-faq.asp#qlistinterviewwaiver10