R programming question

I have this folder and it has about 8 files in it.

In each individual file has data and I did cbind and I got all of the files to go together. but there is just one problem. Every file is different but they have one thing that they all have in common, they all have a column that says participant (to represent the person taking it) and when I cbind all 8 files, I see the column that says participant 8 different times, one for each folder, but I want to make it appear only 1 time for all of the data. is there something I can do, so that it appears only once?