<nick-1> !Add alpha
-nick-2- You are in the Alpha group
<nick-1> !groups
<nick-2> Group Alpha 1 users
<nick-2> Group Beta 0 users
<nick-1> !Add beta
-nick-2- You are in the Beta group
<nick-1> !groups
<nick-2> Group Alpha 0 users
<nick-2> Group Beta 1 users

Code:
on $69:text:$(/^[!](groups)$/Si):#: {
  if $regml(1) = groups { msg # Group Alpha $numtok(%alpha,32) users | msg # Group Beta $numtok(%beta,32) users }
}

on *:text:*:#:{
  if $strip($1) = !add && !$3 { 
    if $strip($2) = alpha {
      if $istok(%beta,$nick,32) { set %beta $remtok(%beta,$nick,1,32) }
      if !$istok(%alpha,$nick,32) { 
        set %alpha $addtok(%alpha,$nick,32)
        notice $nick You are in the Alpha group
      }
    }
    elseif $strip($2) = beta { 
      if $istok(%alpha,$nick,32) { set %alpha $remtok(%alpha,$nick,1,32) } 
      if !$istok(%beta,$nick,32) { 
        set %beta $addtok(%beta,$nick,32)
        notice $nick You are in the Beta group
      }
    }
    else { msg # Group nonexistent. Use: !group  }
  } 
}

Thanks!!!