Something like this in an equation type question placed after a list-radio with qCode "radio" (line breaks inserted for clarity):
{radio=if(age < 25, 'r1',
if(age < 35, 'r2',
if(age < 45, 'r3',
if(age < 55, 'r4',
if(age < 65, 'r5',
'r6')))))}