VR_AD, how to have a coverage for bit toggle, not value

 Now, we have a register like
reg_def  DATA_REG  REG_FILE  12'0x024 { 
   reg_fld resv : uint(bits:24) : R : 0; 
   reg_fld data      : uint(bits:8) : RW : 0 : cov;
}
I want to know whether all bits are toggled in field 'data', but don't care what values are covered.
 I know it could be written as:
        ranges = {
                       range([1'b0..1'b1],  "0");
                       range([2'b10..2'b11],  "1");
                       range([3'b100..3'b111], "2");
                       range([4'b1000..4'b1111],  "3");
                       range([5'b10000..5'b11111],  "4");
                         ...........
                       range([8'b1000_0000..8'b1111_111], "7"); }

Is it possible that VR_AD provide a easy way to do it? Ofcourse, it's caused by specman coverage behavior, not vr_ad.