I have a List<string> that contains paths, such as:

\Root\Folder1
\Root\Folder1\Folder1a
\Root\Folder1\Folder1a\Folder1aa
\Root\Folder2

Given a given root, such as \Root, I would like to "query" this list to return only the first level values, such as:

\Root\Folder1
\Root\Folder2

And "\Root\Folder1\", would return:

\Root\Folder1\Folder1a

How could I construct a query to do this?