Lightroom: Problem importing from multiple cameras

I have a nice workable import routine set up for the files that are imported from my Canon 7D with the following points:
The Canon utility brings the images from the 7D to my HD
Folder name created by Canon's import utility is YYYY_MM_DD
As the files are already where needed I use an "ADD" style of import into LR, (so the files don't move)

I have just bought a Fuji X100, but its import utility (from camera to HD) creates dated folders of YYYY-MM-DD, and this means that when I go to import X100 images on a day that I have already imported Canon 7D images, (or vice versa) I get TWO sets of identically dated folders because they have the different style of date ( _ versus - )

All other issues appear OK (file names, presets applied on import etc)

I cannot find a way to streamline this either in the import utilities, or at the Lr Import stage, and this is a really annoying problem that seems so easy to put right, if only I could!!

Does anyone know how to solve this type of issue please?

Thanks in advance