You could, but I don't think it would make much sense. If you want to outject a @OneToMany collection as a DataModel why don't you create a bean that extracts the collection from the correct entity when it's accessed by your application. Then your new bean can have the extracted collection outjected using @DataModel.
But a UIData backed JSF component (e.g. h:dataTable) can use a list without wrapping (Set's can be used with some conversion). You loose @DataModelSelection (but I've found that if I want that inside an Entity I've made a bad desgin decision ;)