Affidavit of support for Petitioner and Sponsor USA F4 Visa

[shuvo89]

Hello Everyone

I am in the process of filling in the information at Consular Electronic Application Center and make payments for the F4 Family Based Sponsorship .

Question :

If I would like to add a joint sponsor for Affidavit of Support who is a Friend, What are the process of adding the joint sponsor in the CEAC form ?
There is a payment of 120 USD for the Primary Petitioner who is my Brother but is there an option to add the joint sponsor and pay additional fee of 120 USD for the joint sponsor ?
If not then when I have to upload the Form - I-864. will I upload 2 separate forms one coming from the Principal Petitioner and Another from my Joint Sponsor (Friend) in a single pdf.

If anyone has gone through the process please share your suggestions , thoughts and comments

Would appreciate some clarification on this .

Thanks