InnoDB foreign key problem

hey guys.. wonder if anyone might be able to help with my current situation.. ive got 2 tables :

DROP TABLE IF EXISTS users;

CREATE TABLE users (
usr_id int unsigned NOT NULL auto_increment,
usr_name varchar(30) NOT NULL unique key,
usr_pass varchar(32) NOT NULL,
etc..

usr_level int unsigned NOT NULL unique key default '1',

PRIMARY KEY (usr_id),
FOREIGN KEY (usr_level) REFERENCES user_levels (l_level)
) TYPE=InnoDB;

and

DROP TABLE IF EXISTS user_levels;

CREATE TABLE user_levels (
l_level int unsigned NOT NULL unique key default '1',
l_level_desc varchar(100) NOT NULL default '',
PRIMARY KEY (l_level)
) TYPE=InnoDB;


recently i was getting errno150 (cant write table) until i realised i had to add "unique key" to "usr_level" in users table so that it matched the "unique key" attribute that "l_level" has in user levels table.. (InnoDB requires this)

now it adds fine.. but the problem after adding the unique is that i cant have many users with same access level (which i wanted)..

can anyone recommend a way under innodb to keep the l_level in user_levels unique.. but not its foreign key in users so that it can be a 1 to many relationship?

thanks for your help!!

seem to of sorted it.. but adding KEY(usr_level) or INDEX(usr_level) to users table..