Recording data stream + sorting

Hi all, 

I'm using some motion capture hardware (separate Python application) which I've instructed to output:

"1 (unique integer ID of 'tracker point', there are up to 150); x coordinate, ycoordinate, z coordinate"

Sending the strings via UDP/ghowl where they come in one at a time like so:

"ID, point".. "ID,point".. "ID, point"

I want to record the points all in different lists, where the list is defined by the ID, so:

"1; 5.0,5.0,5.0" gets put into a list with "1; 4.0,4.0,4.0" and "1; 3.0,3.0,3.0" 

thanks in advance