Call Lars at Pro-Source Caribe in Sos?a. They sell glass pool tiles, grouts and special adhesives. They also offer construction and installation. Note that there is a big difference between pool tile and ceramic that you use in your bathroom or kitchen.
you could enquire at pro source(as suggested above) its next to el choco where we had lunch, they are expensive but have the proper glass tiles , some places use ones with only a glazed surface which are really only good for showers, have you had any quotes from anyone that builds pools