How to implement multi-user canvas where each canvas created is allocated to particular user


Hullo, i have finsihed implementing whiteboard where multiple users can draw simultaneously on the same board.
I have interest in implementing drawing board where group of users are allocated to specific canvas/drawing board… I would love love to integrate this in elearning platform…
So far this is what I have tried.
I first define all the drawing function under one big function
`if (Meteor.isClient()) {
this.Pad = function Pad(id){
var canvas = $(‘canvas’);
var ctx = canvas[0].getContext(‘2d’);
var drawing = false;
var color = “”;

Then create an instance of the function by particular uservar pad;
Meteor.startup(function() {
Deps.autorun(function() {
if(pad) {
var padId = Session.get(‘padId’);
pad = new Pad(padId);

I appreciate your help in advance…
if u can also apply the analogy of the group chat system where where we use channels … it can be the best