Are all the TVs the same size or are they different sizes and model numbers? Do you have any of the manuals for them? Are the remotes you have the same model number?
With the model number and screen size of all four TVs and the model numbers of the two remotes, you should be able to contact Sony and find out if you need to buy more remotes or if you can just program the remotes to work with the various TV sets.
You aren't giving us much to work with so try contacting Sony first but be sure that you have the size and model numbers for the TVs and the remotes.