replace mcedit with emacsclient without chaning $EDITOR

[Haines Brown KB1GRM ET1]

With advancing age, keeping competitive keybindings straight is more 
of a challenge, and so I'd like to replace mcedit (as much as I like 
it) with emacsclient (which exsts on my machine). 

The way to do this typically seems to change the value of the variable 
$EDITOR, but I don't want to do that system-wide, but only for mc, so 
that F4 brings up emacsclient to edit files, and nano is the default 
editor system-wide.

How would I manage to do that? Unable to find help.

Haines Brown