TIFF files too large for Camera Raw: How to open "part" of large file in Camera Raw

Hello,

I have a now dead link to an adobe forums post about how to deal with large (9+GB) images in camera raw. I seem to remember being able to slection a portion of the image in photoshop and hit a short cut to open that slelection in Camera Raw editor. That selected area would be small enough that ACR would open and edit the image. It could then easily incorporate that change into my large file. I'd have to do it 3 times, but it was easy. Now that link it dead and I need some help. Thanks!!!

It was called "Photoshop Camera Raw Size Limitations"; Link: https://forums.adobe.com/thread/2054850