You might look at the Baker line of horizontal resaws. Woodmizer also makes one. Multi-head units are available. Seems like you have the market to pay back what would be an expensive machine for the typical small shop. Call up door component suppliers and see if they will share what they use for this task, and post your question on Woodweb as well. Here in VT there is an industry group where you might look for answers and no doubt there are others. https://vermontwood.com/