e-mail collectively dumped into desktop first opened

Outlook 6. OS Windows XP. ISP xtra.co.nz
I have a main e-mail account with my ISP and have set up a subsiduary account for my partner. We share a laptop and have separate desktops.
Our problem is this; e-mail held by our ISP for BOTH accounts is dumped into the Outlook of whichever desktop is opened first necessitating us to weedle out each others messages from our own and forward them on to each other.
I've looked at reconfiguring our desktop identities and have contacted our ISP to no avail. Does anyone have any bright ideas? - thanks.

 

Sorted!

I've managed to sort out the problem by going into each desktop's Outlook Express Tools>Message Rules>Mail and requesting that mail from each other's alias not be downloaded from the server. Neat huh?