Situation

I have a field on the form saying like department x or department y

I have a second field a list look up which gets the dropdown list from a SP list.

What i want to do is to set a default to the listlookup dropdown based on a value of field department.

Example

Field Department holds x, y, z

Dropdown holds 100, 200, 300, 400

If department is x then dropdown default is 200 and if it is y then default is 400.

The dropdown list is variable so it can change so i cant say default is always the second or the fourth entry.

I noticed that the listlook has no default function.

So are there ways to get this done?

Regars

Erik