This method does work with with 2 of 3; You perform the method 3 times and divide the encryption seeds like this:
Alex: A1, A2
Bob: B1, A3
Charlie: B2, B3
IMO this is a better method that SSS. SSS relies to heavily on non standard software, must be done on a secure computer and the resulting shares are difficult to record. SSS is better suited for n of m where m is large as this method does not scale favourably; You need to create a share for each subset of m of size n, which grows exponentially as m increases.
http://users.telenet.be/d.rijmenants/en/secretsplitting.htmhttps://bitcoin.stackexchange.com/a/65434/69224