query performance -- another try

First, thanks for your patience and comments to date.

The sql below is being generated in an application server environment, so I am hoping to find a performance improvement without altering the sql -- though I am open to any suggestions.

I explained the situation in previous posts, but did a miserable job with providing the particular query plans that went with the performance problem (not to mention a big problem with parentheses), so let me try again. (My only excuse is, as Willy Wonka said, "So much time, so little to do ...." I know you all have better things to do than wade through my mistakes; I believe I've got it right this time.)

With many OR clauses (> 42 in my case), the optimizer (cost-based, I believe), chooses to use a table scan of a table (Address) with 113,524 records -- 14,115 distinct values for the indexed column, postalCode. Below is the query and then the two plans (before the threshold number of OR clauses and after -- notice the table scan of Address in the latter). (Note: a similar situation arises with IN and I am trying to avoid IN since the max number of elements is 1000 and we sometimes end up with more than that in the query -- it's a zipcodes-within-a-certain-proximity sort of thing.)

(Oracle Enterprice Edition, 8.1.6)

SELECT count(pr.board_certification)
FROM Practitioner pr, AddressXPerson axp, Address a, OrganizationXPerson oxp, Person T1, Specialty s where ((a.postalCode = '07010'
OR a.postalCode = '07020'
OR a.postalCode = '07022'
...
OR a.postalCode = '10007'
)
AND (oxp.role = 'Practitioner' AND axp.role = 'Location' AND a.country = 'USA' AND s.englishDescription = 'Urology' AND pr.remove_from_mdlocator <>
1)) AND T1.personOID = axp.personOID AND axp.addressOID = a.addressOID AND
T1.personOID = oxp.personOID AND pr.personOID = T1.personOID AND pr.specialtyOID =
s.specialtyOID
;

Before threshold:

Execution Plan

   0 SELECT STATEMENT Optimizer=CHOOSE (Cost=170 Card=1 Bytes=74)    1 0 SORT (AGGREGATE)

   2    1     NESTED LOOPS (Cost=170 Card=1 Bytes=74)
   3    2       NESTED LOOPS (Cost=167 Card=1 Bytes=57)
   4    3         NESTED LOOPS (Cost=166 Card=1 Bytes=41)
   5    4           NESTED LOOPS (Cost=163 Card=3 Bytes=93)
   6    5             NESTED LOOPS (Cost=160 Card=3 Bytes=81)
   7    6               INLIST ITERATOR
   8    7                 TABLE ACCESS (BY INDEX ROWID) OF 'ADDRESS' (
          Cost=154 Card=3 Bytes=39)

   9    8                   INDEX (RANGE SCAN) OF 'ADDRESS_POSTALCODE'


           (NON-UNIQUE) (Cost=2 Card=3)


  10    6               TABLE ACCESS (BY INDEX ROWID) OF 'ADDRESSXPERS
          ON' (Cost=2 Card=18844 Bytes=263816)

  11   10                 INDEX (RANGE SCAN) OF 'ADDRESSXPERSON_ADDRES
          SOID' (NON-UNIQUE) (Cost=1 Card=18844)

  12    5             INDEX (UNIQUE SCAN) OF 'PERSON_PK' (UNIQUE) (Cos
          t=1 Card=287899 Bytes=1151596)

  13    4           TABLE ACCESS (BY INDEX ROWID) OF 'PRACTITIONER' (C
          ost=1 Card=86492 Bytes=864920)

  14   13             INDEX (UNIQUE SCAN) OF 'PRACTITIONER_PK' (UNIQUE
          )

  15    3         TABLE ACCESS (BY INDEX ROWID) OF 'SPECIALTY' (Cost=1
           Card=1 Bytes=16)

  16   15           INDEX (UNIQUE SCAN) OF 'SPECIALTY_PK' (UNIQUE)
  17    2       TABLE ACCESS (BY INDEX ROWID) OF 'ORGANIZATIONXPERSON'


           (Cost=3 Card=26009 Bytes=442153)


  18   17         INDEX (RANGE SCAN) OF 'ORGANIZATIONXPERSON_PERSON' (
          NON-UNIQUE) (Cost=2 Card=26009)

After threshold:

Execution Plan

   0 SELECT STATEMENT Optimizer=CHOOSE (Cost=175 Card=1 Bytes=74)    1 0 SORT (AGGREGATE)

   2    1     NESTED LOOPS (Cost=175 Card=1 Bytes=74)
   3    2       NESTED LOOPS (Cost=172 Card=1 Bytes=57)
   4    3         NESTED LOOPS (Cost=171 Card=1 Bytes=41)
   5    4           NESTED LOOPS (Cost=167 Card=4 Bytes=124)
   6    5             NESTED LOOPS (Cost=163 Card=4 Bytes=108)
   7    6               TABLE ACCESS (FULL) OF 'ADDRESS' (Cost=155 Car
          d=4 Bytes=52)

   8    6               TABLE ACCESS (BY INDEX ROWID) OF 'ADDRESSXPERS
          ON' (Cost=2 Card=18844 Bytes=263816)

   9    8                 INDEX (RANGE SCAN) OF 'ADDRESSXPERSON_ADDRES
          SOID' (NON-UNIQUE) (Cost=1 Card=18844)

  10    5             INDEX (UNIQUE SCAN) OF 'PERSON_PK' (UNIQUE) (Cos
          t=1 Card=287899 Bytes=1151596)

  11    4           TABLE ACCESS (BY INDEX ROWID) OF 'PRACTITIONER' (C
          ost=1 Card=86492 Bytes=864920)

  12   11             INDEX (UNIQUE SCAN) OF 'PRACTITIONER_PK' (UNIQUE
          )

  13    3         TABLE ACCESS (BY INDEX ROWID) OF 'SPECIALTY' (Cost=1
           Card=1 Bytes=16)

  14   13           INDEX (UNIQUE SCAN) OF 'SPECIALTY_PK' (UNIQUE)
  15    2       TABLE ACCESS (BY INDEX ROWID) OF 'ORGANIZATIONXPERSON'


           (Cost=3 Card=26009 Bytes=442153)


  16   15         INDEX (RANGE SCAN) OF 'ORGANIZATIONXPERSON_PERSON' (
          NON-UNIQUE) (Cost=2 Card=26009)