def chunks(l,n):
    for i in range(0,len(l),n):
        yield l[i:i+n]

OldList=[111111,a,b,c,d,222222,a,b,c,333333,a,d,e,f]
DesiredList=[[111111,a,b,c,d],[222222,a,b,c],[333333,a,d,e,f]]