Photoshop :: Open Multiple Files As Layers

My engineering department produces .ps files that need to be merged into a single Photoshop file as individual layers. Here's what I'd like to do:

1) Drag a set of .ps files onto a droplet

2) For every .ps file, open with same parameters (e.g. 300 DPI, RGB)

3) Adjust Hue/Sat and set Lightness to +50

4) Colorize each layer and adjust saturation to 100%

5) Make each opened file an individual layer in NewFile.psd

6) Close/delete any intermediate files (but not the original .ps's) and leave NewFile.psd open for further editing

My current droplet will do 1-4, but now I'm stuck! How do I take all the open files and make them into layers in a new .psd?

If I can't do this directly, I can save the results of each .ps conversion into a separate .psd, but then I'll need a droplet to convert

each .psd into a layer in NewFile.psd. I can't figure how to do that, because the Override Open/Save setting seems to mess things up.