Two versions of an extension in the same cluster?

Hello,

I've got an extension that supplies functions written in C. Two
databases from the same cluster both use this extension. I understand
how I can load the example--2.0.0.sql file in one database, and
example--3.0.0.sql in another, but from what I can tell both databases
still share the same .so file. Is there any way to provide a separate
.so for each version?

If not, what is the best approach for releasing a new .so that keeps the
old functionality? I guess something this?:

# example--2.0.0.sql
CREATE OR REPLACE FUNCTION
myfunc(anyarray)
RETURNS integer
AS 'example', 'myfunc_v2_0_0'
LANGUAGE c IMMUTABLE;

# example--3.0.0.sql
CREATE OR REPLACE FUNCTION
myfunc(anyarray)
RETURNS integer
AS 'example', 'myfunc_v3_0_0'
LANGUAGE c IMMUTABLE;

Thanks,
Paul