I\'m using the built-in group service to pull a list of usernames...
function getUsersInGroup(group) {
var usersInGroup = GroupsApp.getGroupByEmail(group).
As @TheMaster pointed out, a simple loop with the map function worked well. Here's what I did:
function writeArrayToColumn(array) {
var mainSheet = SpreadsheetApp.getActiveSheet();
var newArray = array.map(function (el) {
return [el];
});
var range = mainSheet.getRange(2, 1, newArray.length, 1);
range.setValues(newArray);
}