There are two ways (At least)
1. Use Calculated dimension or Expression in the listBox:
Create a new listbox, and choose ‘Expression’ from list of fields. Now put If(Field=Field1 or Field=Field2, Field) as your Expression to show only Field1 and Field2 values in the lsitbox.
2. Use a new table in the model, linking to the desired field, but with only the values that you want to display. Use this dimension in the Listbox.
Insted of selecting a Field in the Field drop-down select <Expression> and then use the following expression:
=If( Year ( Date ) = 2015 , Date )