problem importing groups within address book from outlook express to thunderbird

I would like to switch from Outlook Express to Thunderbird as my mail
client. The problem I am having is when I import my address book from
Outlook Express to Thunderbird, it will not copy the "groups" (refered to as
"mailing lists" on Thunderbird) to Thunderbird's address book. Or rather it
copies the group headers, but with no contacts attached to the groups. It
looks to me like I would have to manually retype in all the contacts that I
designate to the various groups I have set up, which would take an
incredibly long time. Any suggestions?

My operating system is Windows 98 if that makes any difference.

Thanks,
tee

 

Drag addresses from the address book's list in the right pane and drop
them on the mail list name in the left pane.