how to make sponsorship letters from 2 sponsors for F-1 visa?

I am changing my status from H-4 to F-1. I need letter of sponsorship addresed to USCIS from both sponsors. Can somebody plz tell me about the Format of letter. what should be its matter as none of the sponsor can say for full amount. Should both sponsors write their individual letters or i should make a single letter mentioned by both. Plz suggest

You can submit individual letters w/ each mentioning the dollar amount committed. Then you can add a cover letter explaining that you have 2 sponsors and have ecnlosed both sponsorship letters in the package.