[Gnuplot-info] Trouble with bar colors and separation

[<gp...@bl...>]

Hi,
I would like to have 3 (or more) groups of bars, each group in its own colour. Each group shows the same points over time. I don't want to mix them in the normal way. 
However, until now I have not been able to produce this.
Example 1, seems to be the correct way to do it. I get more or less what I want, but only with a single colour. 
In example 2, I get the colours to work the way I want, but the group names are not working and the groups are no longer separated?
How can I get the group names back and separate the bar groups like in example 1?
Ideally I would like to have the points in each group numbered 1,2,etc and the groups with colours in a key. Is there a way to get exactly what I want? 
Thanks,
J.
Example data:
Time1;15;11;12;13;11;10;10;11;15;11;12
Time2;8;9;8;7;8;10;11;8;9;12;13
Time3;4;5;6;4;3;4;5;6;7;2;3
Example 1 (single colour):
set auto x
set yrange [0:16]
set ylabel 'Number'
set xlabel 'Group'
set style data histogram
set style histogram cluster gap 5
set style fill solid border rgb "black"
unset key
set datafile separator ";"
plot \
'data.dat' using 2:xtic(1) ls 1, \
'data.dat' using 3:xtic(1) ls 1, \
'data.dat' using 4:xtic(1) ls 1, \
'data.dat' using 5:xtic(1) ls 1, \
'data.dat' using 6:xtic(1) ls 1, \
'data.dat' using 7:xtic(1) ls 1, \
'data.dat' using 8:xtic(1) ls 1, \
'data.dat' using 9:xtic(1) ls 1, \
'data.dat' using 10:xtic(1) ls 1, \
'data.dat' using 11:xtic(1) ls 1, \
'data.dat' using 12:xtic(1) ls 1
Example 2 (force muli-colour, but problems with group names and separation):
set auto x
set yrange [0:16]
set ylabel 'Number'
set xlabel 'Group'
set style data histogram
set style histogram cluster gap 5
set style fill solid border rgb "black"
unset key
set datafile separator ";"
set style line 1 lc rgb 'blue'  
set style line 2 lc rgb 'green' 
set style line 3 lc rgb 'yellow' 
plot \
'data.dat' every ::0::0 using 2:xtic(1) ls 1, \
'data.dat' every ::0::0 using 3:xtic(1) ls 1, \
'data.dat' every ::0::0 using 4:xtic(1) ls 1, \
'data.dat' every ::0::0 using 5:xtic(1) ls 1, \
'data.dat' every ::0::0 using 6:xtic(1) ls 1, \
'data.dat' every ::0::0 using 7:xtic(1) ls 1, \
'data.dat' every ::0::0 using 8:xtic(1) ls 1, \
'data.dat' every ::0::0 using 9:xtic(1) ls 1, \
'data.dat' every ::0::0 using 10:xtic(1) ls 1, \
'data.dat' every ::0::0 using 11:xtic(1) ls 1, \
'data.dat' every ::0::0 using 12:xtic(1) ls 1, \
'data.dat' every ::1::1 using 2:xtic(1) ls 2, \
'data.dat' every ::1::1 using 3:xtic(1) ls 2, \
'data.dat' every ::1::1 using 4:xtic(1) ls 2, \
'data.dat' every ::1::1 using 5:xtic(1) ls 2, \
'data.dat' every ::1::1 using 6:xtic(1) ls 2, \
'data.dat' every ::1::1 using 7:xtic(1) ls 2, \
'data.dat' every ::1::1 using 8:xtic(1) ls 2, \
'data.dat' every ::1::1 using 9:xtic(1) ls 2, \
'data.dat' every ::1::1 using 10:xtic(1) ls 2, \
'data.dat' every ::1::1 using 11:xtic(1) ls 2, \
'data.dat' every ::1::1 using 12:xtic(1) ls 2, \
'data.dat' every ::2::2 using 2:xtic(1) ls 3, \
'data.dat' every ::2::2 using 3:xtic(1) ls 3, \
'data.dat' every ::2::2 using 4:xtic(1) ls 3, \
'data.dat' every ::2::2 using 5:xtic(1) ls 3, \
'data.dat' every ::2::2 using 6:xtic(1) ls 3, \
'data.dat' every ::2::2 using 7:xtic(1) ls 3, \
'data.dat' every ::2::2 using 8:xtic(1) ls 3, \
'data.dat' every ::2::2 using 9:xtic(1) ls 3, \
'data.dat' every ::2::2 using 10:xtic(1) ls 3, \
'data.dat' every ::2::2 using 11:xtic(1) ls 3, \
'data.dat' every ::2::2 using 12:xtic(1) ls 3