Can I put restraints on the predicted structures?

Hello,

I have one of the structures in complex named as one collagen that is triple helix wound together. In the prediction, I don't want alphafold to predict the collagen structure, as it is a known structure. Is there any way to achieve this? I have tried to put a parameter as "-template", but it didn't work and told me there was no template for the structure.

Thank you!
-Qianchen