Parallel Scaling of a pgplsql problem

Hi all:
Can someone please guide me as to how to solve this problem? If this is the wrong forum, please let me know which one to post this one in. I am new to Postgres (about 3 months into it)

I have PostGres 9.0 database in a AWS server (x-large) and a pgplsql program that does some computation. It takes in a date range and for one pair of personnel (two employees in a company) it calculates some values over the time period. It takes about 40ms (milli seconds) to complete and give me the answer. All good so far.

Now I have to run the same pgplsql on all possible combinations of employees and with 542 employees that is about say 300,000 unique pairs.

So (300000 * 40)/(1000 * 60 * 60) = 3.33 hours and I have to rank them and show it on a screen. No user wants to wait for 3 hours,  they can probably wait for 10 minutes (even that is too much for a UI application). How do I solve this scaling problem? Can I have multiple parellel sessions and each session have multiple/processes that do a pair each at 40 ms and then collate the results. Does PostGres or pgplsql have any parallel computing capability.

Thanks, Venki