Group combination of cells based on manual logic or functions

Hi
I have two columns of numerical data as the height and width of door shutters in mm. A combination of the height and the width gives me the size of the door to manufacture. The doors can be resized by 30 mm and as a result I require excel to group the sizes in the maximum 30 mm group so that I can manufacture standard fewer sizes and the ultimate size can be obtained by trimming the finished product. I can't find a combination of functions which will help me do this. Can anyone please suggest? Thanks in advance. Attached is a pic of what I want. Forum.JPG

Hi, try COUNTIFS.
PS easier to get help if you upload your workbook instead of a picture.