Sqlite FTS minimal token size

Question

How to tell Sqlite FTS5 to only index tokens over a certain length ?

The 'prefix=n' option is close but serves prefix-indexing.
The 'tokenize' options don't seem to offer this.

CREATE VIRTUAL TABLE words USING fts5 (  
    title  
    ,content = books  
    ,content_rowid = id  
    ,tokenize = "unicode61 tokenchars '-'"  
);