Hello!

So this is straight forward. Currently we can manage access by forums.
Is there a way to allow only specific member group users to access specific topic?

There are not permissions for individual topics, only for forums.  So if you want group A to only see a certain topic or topics, you will have to create a forum that only that group can see.

Is there a way to redirect users page based on the group the user belongs to?
Basically, I know how to redirect. My question would be, how to take users group as a variable?
Also, would that work if user belongs to multiple groups.
(using javascript)

It depends on the order of the groups.  If a members is in 3 groups, the group that comes first will give that member the permissions of that group.

If you want to have the group as a js variable, you'll have to send a get request to the groups page and use the information sent back by the server. Something like this:

Code:

$(function(){
$.get("/groups", function(data){
/*Codes here*/
})
})

In the callback, the variable data contains the html of the groups page. You can use it that way:

Code:

$(element, data).last()

Element is the selector of the element holding the groups the user belongs to.