Security FAQ
http://support.microsoft.com/?id=207793

Security Whitepaper
http://support.microsoft.com/?id=148555

Detailed steps at
www.jmwild.com/AccessSecurity.htm

More links:
http://www.geocities.com/jacksonmacd/AJMAccessSecurity.pdf
http://www.ltcomputerdesigns.com/Security.htm
http://www.keithwilby.com/

Humm, never heard of spitted databases.
Must be something for the chewing tobacco industry.
Sorry, couldn't resist. :-)

I assume you mean split databases and security, correct?

Here is some great information on splitting databases:

http://www.granite.ab.ca/access/splitapp/index.htm

And here is a lot of information on applying security:

Access User-Level Security:

Security FAQ (the Security Bible):
http://support.microsoft.com/?kbid=207793

Jack Macdonald's Security Document:
http://www.geocities.com/jacksonmacd/AJMAccessSecurity.pdf

Lynn Trapp's Ten Security Steps:
http://www.ltcomputerdesigns.com/Security.htm

Joan Wild's Tips:
http://www.jmwild.com/security02.htm

The Security Whitepaper is also worth reading:
http://support.microsoft.com/?id=148555

Keith Wilby's Instructions (See step-by-step link)
http://www.keithwilby.com/

Hopefully, these should get you going.