Google-sheets – Copying a cell’s background colour to other multiple cells via script

Update (01/10/2019); code is now:

function copyFormatting() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet();
    var fromRangeGJ14 = sheet.getRange("GJ14");
    var toRangeGJ14 = sheet.getRangeList(['N9','O10','P11']);
    var backgroundsGJ14 = fromRangeGJ14.getBackgrounds();
    toRangeGJ14.setBackground(backgroundsGJ14);
} 

This works very well, but now I want to create many iterations of it in the same sheet, what would be the best way to do this? As an example, if I were to paste the script twice without any optimisation it would look like this:

function copyFormattingGJ14() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet();
    var fromRangeGJ14 = sheet.getRange("GJ14");
    var toRangeGJ14 = sheet.getRangeList(['N9','O10','P11']);
    var backgroundsGJ14 = fromRangeGJ14.getBackgrounds();
    toRangeGJ14.setBackground(backgroundsGJ14);
} 
function copyFormattingGJ15() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet();
    var fromRangeGJ15 = sheet.getRange("GJ15");
    var toRangeGJ15 = sheet.getRangeList(['N22','O23','P24']);
    var backgroundsGJ15 = fromRangeGJ15.getBackgrounds();
    toRangeGJ15.setBackground(backgroundsGJ15);
} 

As you can see the second block differs slightly to the first; is there a tidier way of organising the code as I want to essentially run this probably daily, and I don't mind typing it in manually?

Update (13/09/2019); code is now:

function copyFormatting() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet();
    var fromRangeGI14 = sheet.getRange("GI14");
    var toRangeGI14 = sheet.getRangeList(['N9','O10','P11']);
    var backgroundsGI14 = fromRangeGI14.getBackgrounds();
    toRangeGI14.setBackgrounds(backgroundsGI14);
}

However I am getting this error:

TypeError: Cannot find function setBackgrounds in object RangeList. (line 6, file "Code"

How do I alter this so that the setbackgrounds function applies the background colour from cell GI14 to cells N9, O10, and P11?

Original Post:
Going off this thread here Cell reference with colour formatting

I have modified the script from Vidar to this:

function copyValuesAndFormatting() {
    var sheet = SpreadsheetApp.getActiveSpreadsheet();
    var fromRangeGI13 = sheet.getRange("GI14");
    var toRangeGI13 = sheet.getRange("N9,N10,N11");
    var backgroundsGI13 = fromRangeGI13.getBackgrounds();
    toRangeGI13.setBackgrounds(backgroundsGI13);
} 

I understand that line 4 here does not work (I am trying to reference a range, but I have instead put multiple cells instead of a range – this is intentional as I want to target multiple cells that may not be in a row or in order).

The goal here is copying the background's colour from Cell GI13 to Cells N9, N10, and N11; what do I have to do to the existing script here in order to achieve this effect?

My eventual goal is copying backgrounds from around a hundred cells, to thousands of individual cells, and not necessarily ranges, but individual odd cells.