Workflows or Tutorials for MD Simulations of Protein Multimers?

I have a protein multimer consisting of three proteins, two identical and one different, that I would like to study with MD simulations on Galaxy. However, I cannot seem to find any tutorials or workflows which work for protein multimers.

I have found these two tutorials:

However, both workflows fail when I attempt to use my PDB file containing the three protein chains. Are there any existing workflows for modelling a trimer? If not, how would I go about creating one?