[R] Accounting for clustered data in Rpart or Mvpart

[Luwis Tapiwa Diya]

I am working on data that is in clusters (eg events from persons in
the family).So I have a clustered data set up and would like to build
a tree(regression /classification tree) taking into account this
clustered nature of the data.

Do anybody know how to do this or maybe the code to take into account
the clustered data in rpart