Map two different entities to the same table?

I have a table in my database with a lot of fields. Most of the time I need all those fields. There is one scenario, however, where I only need a few of the fields, and I am loading a ton of rows.



What I'd like to do is add in an Entity manually, and then simply map it to the original table, but delete the columns I don't need. I set this all up, but I get the rather self-explanatory error of:




Problem in mapping fragments
...EntitySets 'FmvHistoryTrimmed' and
'FMVHistories' are both mapped to
table 'FMVHistory'. Their primary keys
may collide.




Is there some other way I should go about this? Again, most of the time all of the columns are used, so I don't want to trim down the original entity and put the "extra" fields into a complex type.