[R] plot by cathegories within a factor

[Rosario Garcia Gil]

Hello

I have a data set summarized like this:

File name= Height

Group Ind Age Trait  
1     1	1	20
1	1	2	21
1	2	1	22
1	2	2	21
1	3	1	24
1	3	2	45
1	4	1	23
1	4	2	26
2	1	1	45
2	1	2	12
2	2	1	25
2	2	2	26
2	3	1	45
2	3	2	43
2	4	1	23
2	4	2	47
.
.
.


I would like to plot Trait ~ Age but a different plot for each Group.
I tried:
> plot(Height$Trait ~ Height$Age | Group)

But does not work. Any suggestion?

Thanks
Rosario