[ic] Any way to have one product affect the price of another in the cart?

[interchange at thedesignpeople.com]

Hi, I was wondering if anyone has done something like this:
Test of the existance of one or a group of similar products in the cart 
and if they exist then give a discount on another different group of 
products.

For example, buy any mouse and get any mousepad at 1/2 price.

Do the builtin price modifiers / adjustments allow for this or with this 
need to be a custom job?

Thanks for any advice,

Mike K