[PyMOL] Help with selecting interface residues between two structures

I am a relatively new PyMOL user and would like to get some helps from the community.

I have two structures for the same antibody-antigen complex (with three chains: light chain L, heavy chain H, and an antigen chain A) .
Structure "base" is the experimental true structure, structure "pred" is the predicted structure. My goal is to determine how close the predicted interface is w.r.t. the experimental truth.

I first select the interface residues as defined by "base"

load base.pdb
load pred.pdb
select int_base, byres(base & (/base//H+L around 5))

How do I select the same corresponding residues in object "pred"?

In addition, what if in the pred structure, chains are named A, B, and C, corresponding to base structure L, H, A, respectively, how will I handle that?
(I was planning to rename the chains, if there is no nice trick to transfer the selections from base to pred)

Thanks!