Bridge Automate "Load Files Into Photoshop Layers" For Stacks Into Photoshop Action

Hello there, I am having a tough time implementing something that will greatly speed up my workflow. Essentially, I need to find a way to automate the "Load Files Into Photoshop Layers" tool in Bridge. As a quick background, I have to make collages for work every now and then. For example, I have an action that makes a 3x3 collage when you give photoshop 9 images. This process isn't automated as I have to load 9 files into photoshop and then run the action. 

It would be ideal if I could give photoshop a stack of files to perform this action. In bridge, I have different stacks that contain 9 photos each in them. I can't wrap my head around how I can tell photoshop to process each stack individually and run only one action per stack. I believe that all I need is a script that takes a stack of photos and makes a new document in photoshop with each image being a unique layer in this document. Then, I would be able to run my script that can make a collage from those layers. If I were to accomplish this, all I would have to do is separate my photos into stacks and run a batch from Bridge into photoshop. Thank you so much for the help!