Group issue in Outlook calendaring

I have a user, who has setup a group of 5 remote employees in the calendar
for ease of scheduling. He has the necessary permissions to all the
accounts in question, and all of the accounts have set their free/busy to
publish 12 months.

The issue is this, he can see previous months for 2 of the 5 users only. He
can see all future month data, but no past data, except for the 2 users. I
cant find any options that would affect this. The funny thing is, ALL 5 of
these users use Citrix to access their Outlook accounts, so they are all
running an IDENTICAL outlook client, with IDENTICAL settings.

Anyone have any ideas of where I can start looking?

Jeff Rhodes
Network Admin