Repeating Section Binding question

[John]

Hi all,
I have a problem with retrieving data for a repeating section that is made
of 3 parts. The first two parts read one row of data each from different
database tables and populates the values accordingly. The third part is a
nested repeating section reads and returns multiple entries from a different
database table.

As an example, the repeating section displays data about 'Protocols' and
the 3 sub- sections that make up that repeating section can be called B1, B2
and B3. The section B3 returns 'Expense' data. The InfoPath form is to
display the information in a format like this:
B1 for Protocol 1,
B2 for Protocol 1,
B3 for Protocol 1, Expense #1
B3 for Protocol 1, Expense #2
B3 for Protocol 1, Expense #3
---
B1 for Protocol 2,
B2 for Protocol 2,
B3 for Protocol 2, Expense #1
B3 for Protocol 2, Expense #2
B3 for Protocol 2, Expense #3
B3 for Protocol 2, Expense #4
---

The nested repeating table in the third part causes the data source to
return the data as follows:
B1 data for Protocol#1, B2 data for Protocol#1, B3 data for Protocol#1 for
Expense #1
B1 data for Protocol#1, B2 data for Protocol#1, B3 data for Protocol#1 for
Expense #2
B1 data for Protocol#1, B2 data for Protocol#1, B3 data for Protocol#1 for
Expense #3
B1 data for Protocol#2, B2 data for Protocol#2, B3 data for Protocol#2 for
Expense #1
B1 data for Protocol#2, B2 data for Protocol#2, B3 data for Protocol#2 for
Expense #2
B1 data for Protocol#2, B2 data for Protocol#2, B3 data for Protocol#2 for
Expense #3
B1 data for Protocol#2, B2 data for Protocol#2, B3 data for Protocol#2 for
Expense #4

Of course it is not this simple, as there are usually 5-10 Protocols and
5-10 Expenses making retrieving the data in this format and then parsing it
programmatically to weed out the appropriate data a performance issue.

Any ideas on how to do this with in InfoPath more efficiently?

Regards and Thanks,
John