dynamically loaded functions

I've written some c-functions which depend on my code (gnova.so)
as well as a third-party library of functions (oe_chem.so).
Up until now, I've been preloading (in postgresql.conf) both .so's
and it all works fine. To make it easier for my users to install my stuff,
I'd like to avoid the preloading, but this would
require giving 2 .so names in the CREATE FUNCTION statement (I imagine).
So, what I would like to do is something like this:

CREATE or REPLACE FUNCTION cansmiles(varchar) RETURNS varchar
AS 'gnova,oe_chem', 'oe_cansmiles' LANGUAGE 'c' IMMUTABLE STRICT;

but I get this:
ERROR: could not access file "gnova,oe_chem": No such file or directory

What I'm doing now:
CREATE or REPLACE FUNCTION cansmiles(varchar) RETURNS varchar
AS 'gnova', 'oe_cansmiles' LANGUAGE 'c' IMMUTABLE STRICT;
requires preloading of oe_chem.so to work.

Is there any way I can associate oe_cansmiles with 2 .so's without
preloading?

More info:
oe_cansmiles is in gnova.so, but there are functions
in gnova.so that are in oe_chem.so.

TJ