Price increase in 1 SECTION

[mac]

How can I increase the price of 1 section of my store by 3%?
For example I have :
Guess
Tommy
Levis

I only want to increase the prices in Tommy section by 3%. how can i do that?

[Duncan Rounding]

You could do it fairly easily in Excel. Export the products and sections then change the prices and import again. (Backup first)