What you want to do is create your own POI category for the trip, or perhaps even more than one. For example, MyHotels.ov2, MyRestaurants.ov2, etc. and populate those with the hotels and restaurants of your choice.
Problem ... it's a shame that your ViaMichelin creates a new *.ov2 for each and every location. That really is not practical. It should have been possible to select number of locations and send them as a single file, so it's your tool that's hurting you there. However, that can be fixed by using a text editor to take the contents of those individual 'one line' *.ov2 files and compile them into one or more broader *.ov2 categories (again, e.g., MyHotels.ov2, MyRestaurants.ov2). You'll find the content is in more or less 'human readable' form and can be copied and pasted from one *.ov2 file to another.
It is true that you cannot add to the existing POI file that comes with the TomTom using your current method, though your method makes more sense for what you are doing. The only way to modify existing TomTom POI categories is to make a 'Map Correction' and add a POI to one of their existing categories.