C# casting question: from IEnumerable to custom type-Collection of common programming errors

I have a custom class called Rows that implements IEnumerable. I often use LINQ queries on Rows instances:

Rows rows = new Rows { row1, row2, row3 };
IEnumerable particularRows = rows.Where(row => condition);

What I would like is to be able to do the following:

Rows rows = new Rows { row1, row2, row3 };
Rows particularRows = (Rows)rows.Where(row => condition);

However, I get a “System.InvalidCastException: Unable to cast object of type ‘WhereEnumerableIterator1[NS.Row]’ to type ‘NS.Rows'”. I do have a Rows constructor taking IEnumerable, so I could do:

Rows rows = new Rows { row1, row2, row3 };
Rows particularRows = new Rows(rows.Where(row => condition));

This seems bulky, however, and I would love to be able to cast an IEnumerable to be a Rows since Rows implements IEnumerable. Any ideas?