Distribution Groups

[Tom]

In large distribution groups (60-70 contacts) if one of the addresses is
invalid, sending to the group is EXTREMELY slow. I have seen this one two
completely unrelated systems. One (my problem) is WinXP Pro, Office2k3,
Exchange2k3, all fully patched. The other is a WinXP, Office 2k, using
internet mail.

I find this very wierd since I do not understand why outlook would do
anything more than verify the format of an email address. Yet as soon as
the offending email address(s) are removed the distro list sends at normal
speed.

Any hints??

Thanks!