Hi Bhavit,
I'm guessing that all of the plasmas would be showing the same video?
If this is the case then you can get HDMI to cat 5/6 converters and cat5/6 to HDMI and then you will be able to distribute from a central source to all the plasmas. They have very cheap HDMI to cat 5/6 and vice versa devices at Jaycar.
You would then need a HDMI splitter to send a source video to all the plasmas.
I'm not sure if this is the scenario that you're looking at.
regards, Mark