Flexible-backbone Rosetta design (partial flexibility)

> Hi All,
>
> I have a question regarding flexible-backbone rosettaDesign. I have a protein complex with two chains, and I want to allow the backbone of only ONE chain (the smaller partner) to be flexible. However, although I have "resfile" specified in my run, the backbone of entire complex was moving freely and so the complex got unfolded. Here are the flags included in my run:
> -design -mvbb -read_all_chains -fa_input -repack -ex1aro -ex2aro_only -resfile
>
> Is it not possible to allow PART of the complex backbone to be flexible, or am I doing something wrong?
>
> Any input/information will be greatly appreciated
>
> Shirley