jmc

All the oranges can go in one group, or $3$ can go in one group and $1$ in another group, or $2$ can go in one group and $2$ in another group, or $2$ can go in one group and each of the other $2$ can be in a group by itself.

As a list, we have: $$\begin{array}{rl}& 4\\ & 3,1\\ & 2,2\\ & 2,1,1.\end{array}$$ This gives a total of $\boxed{4}$ possibilities.