Combining multiple records into one based on a key field -- inside one table !

[glenn]

I'm really scratching my head over this one. I'm working with CSV data exported
from Excel, which explains why it's a mess to begin with.

Within a table (or via any other means someone might be able to recommend) I
need to combine multiple records which share two like fields. (If that's not
clear, the real-world explanation is below.)

+----------+--------------+----+----+----+----+----+
| ID | ADDRESS | P1 | P2 | P3 | P4 | P5 |
+----------+--------------+----+----+----+----+----+
| COMP1 | 123 Main St | 1 | | | | |
| COMP1 | 123 Main St | | 1 | | | |
| COMP1 | 123 Main St | | | 1 | | |
| COMP2 | 45 Oak Pl | 1 | | | | |
| COMP2 | 45 Oak Pl | | | 1 | | |
| COMP2 | 45 Oak Pl | | | | 1 | |
| COMP2 | 45 Oak Pl | | | | | 1 |
+----------+--------------+----+----+----+----+----+

Must be distilled to :

+----------+--------------+----+----+----+----+----+
| ID | ADDRESS | P1 | P2 | P3 | P4 | P5 |
+----------+--------------+----+----+----+----+----+
| COMP1 | 123 Main St | 1 | 1 | 1 | | |
| COMP2 | 45 Oak Pl | 1 | | 1 | 1 | 1 |
+----------+--------------+----+----+----+----+----+

So essentially I want to combine all of the 'Px' fields for each ID into one
record.

The real model : The data represents companies (identified by ID) and the
product lines they stock (P1 - P5). Right now, there's a separate rec for each
product line. I need to combine those seperate recs into one.
____________________

I suppose I could import the raw data into separate tables, each with one 'P'
field -- and then combine them into another, but I'm not sure about that
approach either.
____________________

I already tried to make Excel combine before exporting, but had no luck.

Any help will be _greatly_ appreciated. I'm stumped.