UNITED SECURITY <UNSE> TO BUY ROBERT BROWN UNIT United Security Financial Corp of Illinois said it has signed a letter of intent to buy Robert Co. Brown and Co Inc's <RCBI> MAGIC Insurance Group unit. Robert C. Brown and Co would receive newly issued United Security stock. United Security said it is anticipated that such stock would represent a substantial majority of the shares outstanding after the merger. United Security's principal subsidiary is United Security Life Insurance Co of Illinois. The MAGIC Group owns Pilgrim Life Insurance Co of America and Middle Atlantic Life Insurance Co.