SQL & PL/SQL :: Multilevel Collection Comparison Using Sets?

I need to populate a table based on the results of comparing sets of data. I decided to do this using MULTISET EXCEPT, but having created the structure, do not know whether it is actually possible, and if so, what syntax to use.

I have created:

CREATE OR REPLACE
TYPE NUMBER_TBL IS TABLE OF NUMBER;
/

CREATE OR REPLACE
TYPE PACKAGE_OPTION_GROUP_OBJ AS OBJECT( ID NUMBER, benefits NUMBER_TBL )
/

CREATE OR REPLACE
TYPE PACKAGE_OPTION_GROUP_TBL AS table of PACKAGE_OPTION_GROUP_OBJ
/

I have populated the following:

selectedTable PACKAGE_OPTION_GROUP_TBL := PACKAGE_OPTION_GROUP_TBL();

defaultTable PACKAGE_OPTION_GROUP_TBL := PACKAGE_OPTION_GROUP_TBL();

groupTable PACKAGE_OPTION_GROUP_TBL := PACKAGE_OPTION_GROUP_TBL();

comparisonTable PACKAGE_OPTION_GROUP_TBL := PACKAGE_OPTION_GROUP_TBL();

Once populated they contain the following data:
***selectedTable***
GROUP_ID : 121
BENEFITS : 161
---------------------------
GROUP_ID : 123
BENEFITS : 165
BENEFITS : 167
---------------------------

***defaultTable***
GROUP_ID : 121
BENEFITS : 161
---------------------------
GROUP_ID : 122
BENEFITS : 162
BENEFITS : 163
---------------------------

***groupTable***
GROUP_ID : 121
BENEFITS : 161
---------------------------
GROUP_ID : 123
BENEFITS : 165
BENEFITS : 166
---------------------------

I first need to compare the ID field only of selectedTable with defaultTable to find where they differ, something like

comparisonTable := selectedTable MULTISET EXCEPT(ID) defaultTable

I am expecting the result to be something like:
***comparisonTable***
GROUP_ID : 123
BENEFITS : 165
BENEFITS : 167
---------------------------

However, I don't know if this is possible and if so, what the syntax would be.

At a later stage, I will need to compare the benefits between selectedTable and groupTable, where the GroupID's match, which is why I have the tables structured in this way.