Sewing "ties" on outdoor cushions

I have about 60 canvas cushions for our bar here at the hotel. They came with ties - two thin strings of the canvas that we can use to tie them down to the furniture. I want to make those ties into loops. So they need to be sewn together. Because of the size and number of cushions - I want to do this on site. I am searching for someone with a machine that will be capable of handling the heavy canvas ties, and can sew them together so they will survive living outside for the season. And someone who is willing to bring their machine to the hotel and set up to do the project here.