grouping a Lookup

grouping a Lookup

Hi there,

Here's the situation i have:

In the Main form, i have a Lookup field called year.  This is setup as a dropdown.  It's lookup definition is to grab Recruitment_Year from Reference form.

Recruitment_Year in the Reference form can be the same for multiple records.  As in, i can have records form that may be:

Recruitment_Year/Recruit_Name

2008/Jack Black
2009/John Doe
2009/Susie Q
2010/Jennifer Brown
2010/Alan Partridge

Currently, if i pull up this Lookup picklist in the Main Form, it shows each Recruitment_Year uniquely, so it looks like:

2008
2009
2009
2010
2010

I wish all "like" years to show up in the picklist only once, so that it only displays:

2008
2009
2010

How is this achieved?

Thank you!