Linking separate JSON objects together to create a GeoJSON Feature Collection in Leaflet

HTML

<script src="http://cdn.leafletjs.com/leaflet-0.7.2/leaflet.js"></script>
<link rel="stylesheet" href="http://cdn.leafletjs.com/leaflet-0.7.2/leaflet.css">
<div id="map"></div>

CSS

html, body, #map {
    height: 100%;
    width:100%;
    padding:0px;
    margin:0px;
    background: white;
}

JavaScript

var map = L.map('map').setView([39.74739, -105], 13);

// set source for map tiles
ATTR = '&copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, ' +
'<a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a> | ' +
'&copy; <a href="http://cartodb.com/attributions">CartoDB</a>';

CDB_URL = 'http://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png';

// add tiles to map
L.tileLayer(CDB_URL, {attribution: ATTR}).addTo(map);


var freeBusGeom = {
    "type": "FeatureCollection",
        "features": [{
        "id": 1,
            "type": "Feature",
            "geometry": {
            "type": "LineString",
                "coordinates": [
                [-105.00341892242432, 39.75383843460583],
                [-105.0008225440979, 39.751891803969535]
            ]
        }
    }, {
        "id": 2,
            "type": "Feature",
            "geometry": {
            "type": "LineString",
                "coordinates": [
                [-105.0008225440979, 39.751891803969535],
                [-104.99820470809937, 39.74979664004068]
            ]
        }
    }, {
        "id": 3,
            "type": "Feature",
            "geometry": {
            "type": "LineString",
                "coordinates": [
                [-104.99820470809937, 39.74979664004068],
                [-104.98689651489258, 39.741052354709055]
            ]
        }
    }]
};

var lightRailStopGeom = {
    "type": "FeatureCollection",
        "features": [{
        "id": 11,
            "type": "Feature",
            "geometry": {
            "type": "Point",
                "coordinates": [-104.98999178409576, 39.74683938093904]
        }
    }, {
        "id": 12,
            "type": "Feature",
            "geometry": {
            "type": "Point",
                "coordinates": [-104.98689115047453, 39.747924136466565]
        }
    }]
};

var bicycleRentalGeom = {
    "type": "FeatureCollection",
        "features": [{
        "id": 51,
           ...