How to assign apps to cwm groups?

Hello,

I'm trying to assign xterm to group 1 and firefox to group 2. Then, I'd
like to only see a specific group at any given time.

After logging in, I start xterm. Then I start firefox. Problem is
firefox opens right on top of my terminal. I expected it to open in
group 2 such that either it's not visible till I press 4+2 or start
firefox in group 2 and move me to group 2 automatically. Is that not how
groups work?

Also, with the config below and firefox and terminal open, when I press
4+1 nothing happens (I still see firefox and xterm stacked). When I
press 4+2, both windows disappears.

Can someone please let me know how I can configure groups to work a
little like workspaces in i3, if that's possible?

cwmrc content:

sticky no

bind-key 4-Return "terminal"
bind-key 4-d "menu-exec"
bind-key 4S-r "restart"
bind-key 4S-e "quit"
bind-key 4S-q "window-close"

bind-key 4-1 "group-only-1"
bind-key 4-2 "group-only-2"
bind-key 4-3 "group-only-3"

# Groups
autogroup 1 "xterm,XTerm"
autogroup 2 "Firefox"

# Mouse bindings
bind-mouse M-2 window-lower
bind-mouse M-3 window-resize

--
Sadeep Madurange
PGP: 103BF9E3E750BF7E