Not sure but worth a try.
Open Outlook Express and select Tools > Message Rules > Mail.
In order for separate email accounts to drop into separate folders you need to ensure that message rules similar to the following have been created.
Click on New Rule, in the top section check the box that says 'Where the to line contains people'.
Select the words 'Where the to line contains people' and type in the email account. Then in the box 'Select the actions for your rule' check the 'Move it to the specified folder'.In the third box select the specified folder to move the messages to.
Save the message rule - repeat as necessary for each separate email account.
Hope it helps.