Help retrieving all elements from linked models intersecting a Bounding Box

I am trying to retrieve all elements from linked models that intersects a bounding box. The code I have only retrieves the elements from the active model. See below for current code. I am relatively new to Dynamo and code writing and I would greatly appreciate any help anyone can offer.

import clr
import Revit
import RevitServices
from Autodesk.Revit.DB import *
from System.Collections.Generic import List
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
doc = DocumentManager.Instance.CurrentDBDocument

#Functions for list handling
def ProcessList(_func, _list):
return map( lambda x: ProcessList(_func, x) if type(x)==list else _func(x), _list )

#Preparing input from dynamo to revit

def ToRevit(item):
return item.ToRevitType(True)

if isinstance(IN[0], list):
bblist = ProcessList(ToRevit, IN[0])
bblist = [ToRevit(IN[0])]

def collectElementsInBB(bb):
outline = Outline(bb.Min, bb.Max)
filter = BoundingBoxIntersectsFilter(outline)
collector = FilteredElementCollector(doc, doc.ActiveView.Id).WherePasses(filter)
return [e.ToDSType(True) for e in collector]

OUT = ProcessList(collectElementsInBB, bblist)