I would like to know if someone knows how to put two legends in the same axis.

Exmaple : I've one bar chart showing 3 measures (A,L,M) and each group of maesures in this case are 3, i want to split by week, the x axis will be like this :

_______________________
A | L | M | A | L | M |
__1WEEK___|___2Week___|

is there someone that knows how to do that???

thanks :))