Create a new user field of type String. Call it Hidden Track #. For any given hidden track, set the value you want as a decimal, such as 0, or 1.5, so that the hidden tracks would sort numerically in the correct location.
Now, replace your Track # columns with an expression column, such as :
if(!isempty([Hidden Track #]), [Hidden Track #], [Track #])&datatype=[number]
This will use Hidden Track # if it exists, otherwise the normal Track #, and treats the entire expression as a number for proper sorting. Set up your view to Sort on Hidden Track # instead of Track #.