[R] Multiple methods in models

[Marshall Feldman]

Hi,

The model specification formula language introduced in Chambers and 
Hastie potentially handles rather complex models. Typically the user 
specifies the model and in a separate argument specifies the method. For 
example, one specifies a general linear model with glm(formula,family). 
But with a complex model, one may want to use different methods to 
compute different parts of the model. This seems to imply either 
extending the formula language to integrate method specification as part 
of the model specification or extending the separate method argument 
(family in the case of glm) to include multiple methods along with a way 
to relate them to different parts of the model.

I've looked to see if any packages do such a thing and have found none. 
I've also looked through several documents on R without success.

Does anyone know of a package, document, or other thing in R-land that 
does something like this?

Thanks.
     Marsh Feldman