I have a vbs script that I'm using to add a global group to the local administrators group. (See Below)

Set oNet = CreateObject("Wscript.Network")
Set com = GetObject("WinNT://" & oNet.ComputerName)
Set LocalGroup = com.GetObject("group", "Administrators")
Set DomainGroup = GetObject("WinNT://MYDOMAIN/WGA,group")
LocalGroup.Add(DomainGroup.AdsPath)
LocalGroup.SetInfo

What I need help with is adding a statement where it would check to see if the group is already added before it does anything. If the group is not added then it will proceed with adding the group. Or if the group is already in the local admin group then the script does nothing. Any help?