Hi,
the following werk is a solution:
Werk #10848: mk_oracle: Support for configuration directory
This will be part of 1.7 but could easily backported to 1.6 as well.
Place configuration files in /etc/check_mk/mk_oracle.d. The definition will overwrite entries from /etc/check_mk/mk_oracle.cfg from the bakery.
Regards
Thorsten