I believe that attB sites are on your e.g. PCR product. Which permits them to be dropped into a DONR plasmid containing attP sites (and a ccdB cassette), creating an ENTR plasmid (contains your gene, has ccdB removed) for the LR reaction with a DEST (destination) vector, resulting in your expression vector, that will be used for whatever your application actually is. This is how we do it in my work flow.
Oh, sorry. I miss understood your objective. :) I would expect any attB site harboring construct to transfer to a P site harboring one. I have not done that, but, I would expect it to work.