I took out your variable for my testing so you will need to add it back in...  Anyway, I think this does what you need - eventhough it is extremely ugly.  I would keep looking for a better way to do it.  I don't think this will be very effecient.

SELECT r.year, r.qtr, r.industry_code

 FROM rpt_calc_data r INNER JOIN

   (select year, qtr, min(empl) as empl

    from rpt_calc_data r

    where r.nd = 0

    group by year, qtr) AS Z ON r.year = z.year and r.qtr = z.qtr and r.empl = z.empl

WHERE r.nd = 0

AND NOT EXISTS

(SELECT * FROM (

select r.year, r.qtr,  v1.empl, min(industry_code) industry_code

FROM

(

select year, qtr, min(empl) as empl, count(*) as count

from rpt_calc_data r

where r.nd = 0

group by year, qtr

having count(*)>1

) v1

INNER JOIN rpt_calc_data r

ON r.year = v1.year and r.qtr = v1.qtr and r.empl = v1.empl

WHERE r.nd = 0

GROUP BY r.year, r.qtr, v1.empl

)  vt WHERE vt.empl=r.empl)

UNION ALL

select year, qtr, industry_code FROM

(

select r.year, r.qtr,  v1.empl, min(industry_code) industry_code

FROM

(

select year, qtr, min(empl) as empl, count(*) as count

from rpt_calc_data r

where r.nd = 0

group by year, qtr

having count(*)>1

) v1

INNER JOIN rpt_calc_data r

ON r.year = v1.year and r.qtr = v1.qtr and r.empl = v1.empl

WHERE r.nd = 0

GROUP BY r.year, r.qtr, v1.empl

) vt