This is how Qlik works by default if you used the Dimension setting for "Limitation" (and then e.g. "Fixed - top 10"). Clicking "Others" will perform a selection on the dimension field which includes all values in the table not currently displayed.
Note that this will not be able to select null values in the dimension so if you have those and want them included, you will need to replace the nulls with something that can be selected.
I'm not sure what your object is doing, but as far as I know this is the default behavior assuming your "Others" field is achieved through the dimension limitation and your dimension field allows selections and isn't some sort of complex calculated dimension which can't be selected on. I've confirmed this with a test app.