pullups with resistance band in door attachment

[musculArgirl2]

doing p90x and p90x you do a lot of pullups, chinups, etc. The resistance band i use i don't know if it's resistant enough. Do you think it would be okay to use two resistsant bands and use them both at the same time?

[Boss Man]

It should be fine, as long as they don't get twisted or tangled up together in some way.