class triangle object

Hello, i m looking for a way to make a S4 triangle like the data "auto" in the démo. 
my initial.data is a SQL table with these columns: entity,lob,origin,dev,typemesure(cumpaid,incurred), value to sim.
i would like create a only one  triangle collection aggregate by entity,lob,typemesure.
how  Can i do this?
thanks 