Say we have some data like this:

```
dta <- data.frame(
group = rep(letters[1:8], each=1000),
x = runif(8000), y=runif(8000)
)
```

I would like to produce a Lattice plot containing y ~ x for each group. But, with groups a-d on the first row, and e-h on the second row. i.e., I would like to do the equivalent of

```
qplot(x=x, y=y, data=dta) + facet_wrap(~ group, nrow=2)
```

But in Lattice. What is the best way to do this?