Without that info, we can only guess at how your gear could be connected.
Might be tough to pull this off via HDMI unless your laptop could simultaneously output via the 3.5mm jack (audio)*and* the HDMI (video). If your laptop has VGA, then you could easily connect the laptop to the Epson for video, then output audio from the audio jack to the Sony. YMMV.
Today I bought a sony BDV- E2100 home theatre system. I also have an epson EB- S120 projector. I want to be able to watch movies from my laptop on the project whilst recieving the audio from the home theatre system but I have no clue on how to wire it up.
P.S not a tech person at all so please bare with me!

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