How to connect Windows XP Guest OS to Server 2008R2 OS

[steveb_ni]

Can anyone advise me as to how I go about connecting a Windows XP Guest OS to my Server 2008R2 Guest OS?
As in, connect to a domain within Server 2008R2?

I'm pretty certain the problem is with the default network connection settings in Virtual Box for the Guest OS's - can anyone tell me what settings I should ideally have to allow the connection?

Thanks in advance!

[FrodoHobbits]

Set them both as "Internal Network" with fixed IP's