Pretty much everything which involves registry changes can be done with a group policy - some things need you to write your own ADM file, however.
I've used regtoadm before now - once you get the registry file you need you can just create an adm and deploy it.
This is the code we use in a machine startup script - it sets it for Word, Excel and PowerPoint
Code:
set oShell=createobject("wscript.shell")
'configure Browse in Same Window Through IE for Office Apps
oShell.regwrite "HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Word.Document.8\BrowserFlags",8,"REG_DWORD"
oShell.regwrite "HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Excel.Sheet.8\BrowserFlags",8,"REG_DWORD"
oShell.regwrite "HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Powerpoint.Show.8\BrowserFlags",8,"REG_DWORD"