PostgreSQL DB split

Hi,

I'm currently using a PostgreSQL DB on my disk memory, but right now I need to split this DB in this way:

a. the first DB (or first DB partion) will be stored in the Flash memory and it will contain the system configuration values;
b. the second DB (or second DB partion) will be stored in the RAM memory and it will contain the state values.
These values will be modified many times and they will be deleted when the system goes down.

I can read that I can create a PostgreSQL DB on the RAMDisk partion, but I'm wondering if is it possible to create
one DB with two schemas in two different memory location (RAM and flash)?

Otherwise, I can create two DBs in two different location (RAM and flash) but is it possible to execute a SQL query
where the join relationship concerns two tables located in the different DBs? Can I use the dblink in order to create
only one DB connection?

Can someone help me? Thanks in advance.

--Tomas