Can I use LSI (Latent Semantic indexing) to get similar docs for several documents at the same time?

I’m working on a Recommander system in which I’m using LSI to get similarities between videos.
I wonder if I can provide to LSI matrix more than one document and get similar docs for all those. In the case of one input doc, it runs perfectly.

I thought to concatenate all input documents into one and get similar docs for this one, but I’m not sure if this would be a good idea.

thanks in advance