Share a Db

I am using Access 2003
I created a database for a PM Program that sometimes requires more than one
person to use the program at the same time. Is there a way to allow this to
happen. I did go into Tools Options Advance tab and make the "default
Open Mode" shared. But if an employee is using the program, I still get a
message that if I make changes to the program, they will not be saved because
someone else is using the program. Can anyone help me or point me in the
right direction????

Thank you - Aurora