Pull Values from List Exluding Matching Values in Second List

The basic question is: Is it possible to pull a list of values out of an array based on a couple of criteria, but exclude them if they exist with certain criteria in a second array?

To be more concrete: I have a spreadsheet tracking a fundraising campaign. Tab 1 is "All Donations" and lists every donation received. Tab 2 is "Pledges" and lists donations that have been promised, but not yet made. I am creating a third tab to pull a summary of the month's activity a committee.

I can successfully pull a list of all of the donations from the past month using this formula:

=INDEX('All Donations'!D:D,SMALL(IF('All Donations'!$C:$C>=(EOMONTH($B$3,-1)+1),IF('All Donations'!$C:$C<=$B$3,ROW('All Donations'!$A:$A))),ROWS($A$31:A31)))

I would like to exclude any donations which show on the Pledges tab as having been applied toward a pledge. This means checking 3 criteria on the Pledges tab - the name (column A), the date (J) and amount (K). If all 3 of these match the data on the All Donations tab, the record should not show on the list.

My best shot at it was adding the red if functions:

=INDEX('All Donations'!D:D,SMALL(IF('All Donations'!$C:$C>=(EOMONTH($B$3,-1)+1),IF('All Donations'!$C:$C<=$B$3,IF('All Donations'!$C:$C<>Pledges!J:J,IF('All Donations'!D:D<>Pledges!A:A,IF('All Donations'!E:E<>Pledges!K:K,ROW('All Donations'!$A:$A)))))),ROWS($A$33:A33)))

Needless to say, it didn't work. So, I'm appealing to anyone brilliant (or at least smarter than me) out there.