[R-SIG-Mac] inferior R or Cocoa R on Mac from Carbon Emacs

[Alexy Khrabrov]

How can I specify whether I want my Emacs/ESS Eval/and-Go commands  
sending either to

-- an inferior R process which I started from ESS=>Start process=>R
-- an existing Cocoa R commander?  For the latter, can ESS start it  
under Mac or I need to start it first?

Ideally, this should be customize'able at run time...

Cheers,
Alexy