Javascript: Iterate over Object Literal Values

I have a standard jQuery plugin set up that creates default settings at the top:

jQuery.fn.myPlugin = function(options) { 
    var defaults = {  
        starts: "0px,0px",
        speed: 250, ...
    };
    o = $.extend(defaults, options);
}

I have another variable called numberOfObjects.

I'm trying to loop through the default variables. For each object found (from numberOfObjects) I need to duplicate the value of the variable value. So, if the numberOfObjects variable is 3, the defaults.starts should be 0px,0px > 0px,0px > 0px,0px. The > is used to split values.

This is what I currently have. X represents the variable name inside defaults. Y represents the variable for the current value of x. I've gotten this far and have no clue what to do next.

for (x in defaults) {   // x is defaults.x
    defaults.x = defaults.x + "> y";
}