Basic example of publishing one server side collection to 2 different client side collections.

gistfile1.js

//Available on Client and Server and is a managed collection
Vehicles = new Meteor.Collection('vehicles');

if(Meteor.isServer){
    Meteor.publish('cars', function () {
    	var cursor = Vehicles.find({type:"car"});
    	var subscription = this;
    	
    	var handle = cursor.observe({
    		added: function (document) {
    			subscription.added('cars', document._id, document);
    		},
    		changed: function (newDocument, oldDocument) {
    			subscription.changed('cars', newDocument._id, newDocument);
    		},
    		removed: function (oldDocument) {
    			subscription.removed('cars', oldDocument._id);
    		}
    	});
    	
    	subscription.ready();
    	
    	subscription.onStop(function(){
    	    handle.stop()
    	});
    });

    Meteor.publish('trucks', function () {
    	var cursor = Vehicles.find({type:"truck"});
    	var subscription = this;
    	
    	var handle = cursor.observe({
    		added: function (document) {
    			subscription.added('trucks', document._id, document);
    		},
    		changed: function (newDocument, oldDocument) {
    			subscription.changed('trucks', newDocument._id, newDocument);
    		},
    		removed: function (oldDocument) {
    			subscription.removed('trucks', oldDocument._id);
    		}
    	});
    	
    	subscription.ready();
    	
    	subscription.onStop(function(){
    	    handle.stop()
    	});
    });
}

if(Meteor.isClient){
    //The 2 unmanaged collection on the client, you will not be able to write to these.
    //Write to the vehicles collection directly instead
    Cars = new Meteor.Collection('cars', {connection:null});
    Trucks = new Meteor.Collection('trucks', {connection:null});
    
    Meteor.subscribe('cars');
    Meteor.subscribe('trucks');
}

Wow, it looks really good. It smells like a new meteor pattern ;)