I have to start grouping my movies too. Any chance you could find a link to the threads you used?
The topic I used to try and figure out how to group my movies is located here:
http://yabb.jriver.com/interact/index.php?topic=75831.0However, it doesn't give detailed instructions on what to do and where so I had to mess around with MC a lot. I'm sure how I finally got it to work isn't the best or easiest way, but at least it's doing what I want for the most part.
From what I can remember, here is what I did:
First, I went through each of my movies(over 300, Ugh!!) and filled in the "Series" tag. For all movies I wanted grouped together I entered something like 'Transformers' Collection. Only did that to begin with but then all the movies I didn't want grouped were lumped into a folder called "Unassigned Expression" so I went back through them again and for each of those I entered the actual movie name in the "Series" tag.
To get them to show in MC I first went to "Tools/Options/Library & Folders/Manage Library Fields" Then I selected "Add New Field" and named it "_Sort_Series_by_DateName"(without the quotes). I set Flags to Video and chose Caculated data and entered the following expression(again, without the quotes): "if(!isempty([Series]),[Date (year)] [Name], [Name])". Once that's done and back to MC standard main screen, go to "VIEW/ADD VIEW/ADD LIBRARY VIEW". In the window that opens, I selected "Empty View", named it "Movies- Grouped" and for location I selected Video\Movies(this may be different for you). Then, I right clicked the new view and selected "Customize View". In the resulting window, I did the following: Set "View As" to Categories. Below that I added two entries. First I hit "Add/Library Field/Series. Believe I left all settings for it at defaults. Then Hit "Add" again, but selected "Expression" this time. Under expression to group by I selected the expression I created earlier. Sorting to "Date (oldest first) and Matching to "Match any". Last step I believe is to go back to Tools/Options and select Theater View. Under Items to show, highlight Movies, select Add/Library Item from Standard View/Video\Movies- Grouped. Once created under items to show, highlight it. I renamed it to just Grouped but you don't have to(Don't rename it in MC statndard view). Then select Rules for Display. Under Rules Add Media Type as Video and Media Sub Type as Movie.
That should do it if I remember correctly. Now when in theater view, it should be a selectable view. Hope this helps!!