executing a procedure withing a procedure?

Hi guys,
I'm re-writing a MS Access frontend in readiness for a postgresql migration
but I am abit stuck since postgres is completely new to me. Anyways, is it
possible to execute a procedure within a procedure?

What I'm trying to do is that in the access frontend, there is a form where
you can generate reports with all the options
(adviser,provider,introducer,plangroup,plantype, and datelist- which sets
two text fields date_start and date_end. Additionally, there are checkboxes
for all the options which are checked when an option has been selected eg
when you choose an adviser. To make things even more complicated, you can
also select an adviser and a datelist so you can records for an adviser for
the specified time period for example.

The idea I have in mind is that I will create pass through queries in VBA
code builder that takes the parameters and does all the processing on the
server and returns the query that is then used to make the report.

What the problem is that there is alot of repetition because of the filters
(subqueries are used in the access queries) so I was hoping there was a way
I could reduce the amount of code i would have to write for the procedure
that returns the qeury results.

I'm also open to any other suggustions on how to tackle this problem.

Cheers,
Ben