Actually it depends on how they were released. Movies are generally released individually with a period of time in between the sequels. Unless they were FIRST shown together before they were , they should be different entries.
OVA's are sometimes also released one disc/episode at a time, but don't get a separate entry for each one... Personally I think we have way too many useless entries for movies that are essentially "movie series", so I'd be happy to see them get combined..
Well being one that have seen every freaking gundam i care altought the seperations of ova/series/movies is of not much interest as long as its consistent