Using both cross-compiled and natively packages on the same nixosSystem

Hi, I’m trying to cross-compile a system image for a raspberry pi 2 from x86_64 linux:

nixpkgs.hostPlatform.system = "armv7l-linux";
nixpkgs.buildPlatform.system = "x86_64-linux";

Most stuff cross-compiles okay, but some packages do not, and I don’t have the time to go in and fix the builds in nixpkgs currently. Is there a way to set things up so that some packages are compiled on armv7l-linux but others are cross compiled? Thanks

Something like this would probably work

{ pkgs, ... }: let
  pkgsNative = import pkgs.path { inherit (pkgs.hostPlatform) system; };
in {
  nixpkgs.overlays = [(self: super: {
    inherit (pkgsNative) foo; # Natively compile foo