[R-sig-ME] robust linear mixed model

[Ahmad Rabiee]

Hi

 I have a dataset with some outliers or influential observations, and intend to do a mixed model regression. I am looking for procedures or   a package that can do "robust linear mixed model", to account for the outliers or influential observations or groups.
 There are similar functions for fixed models (rlm) in MASS package, but I haven't been able to find anything on mixed models.

Thanks

Ahmad