Active Directory ... An invalid dn syntax has been specified

Hi
I use some code to check if people are in a group in Active Directory.
If the group has an '&' in it then I run into problems.
DirectoryEntry entry = new DirectoryEntry("LDAP://adserver/CN=" + theGroup + ",OU=Distribution Groups,OU=Accounts,DC=ourdomain,DC=net");
 
I tried to do ...
theGroup = theGroup.Replace("&", "\\&");
 b ...