You can run two consecutive commands with different masks.

Or you can get close, but not exactly, to what you ask for by doing:
var FILEMASK = "*.[gc][ps][gv]";

In winscp scipt, can it be possible to give multiple masks eg

// Mask of files to search for
var FILEMASK = "*.gpg";

So, above command consider only gpg files, but I need .gpg and .csv files. How to do this in one file mask.