Flag Items in MS Outlook help needed?

Hi,

In a firm that I previously worked for, the department has a group E-Mail box to recieve external work related E-Mail's.

When the E-Mails came into the box, they would flag them and allocate them to the correct person.

Now that I have joined a new firm, I want to do the same thing, but when I go to flag an item, they do not have it setup like the firm before.

So I am assuming that the previous firm, customised their Outlook so that they could input people's name into the drop down option box of the flagging function.

Does anyone know how I can customise this?

Many thanks,

Brendon.