pgadmin user access control features

Hello,

So I plan on deploying a Postgres DB in an military project. On our admin end we are using the tool to help set up the
databasefor delivery. Now the problem comes once the system is delivered. The database is used to record all the system
messagesfor easy retrieval. This feature is rarely used and is only there if the system accidentally kills someone
(Militarygrade security system with guns), the client needs to be able to reconstruct the event.  

In order to do this the client needs an interface to access the database. The two options are to give them a query tool
wedesign so we can restrict their actions (to prevent the database from being screwed up). The other option would be to
restricttheir access in the pgadmin tool installed on the system itself and prevent them from deleting data. Is it
possibleto set up accounts within the tool and secure the admin access for ourselves so they can only run certain types
ofqueries on their own account.  

I know this is possible with MS SQL Server tools, but we're bound to open source solutions. Any information would be
useful. 

Thank you,
Dan