Yes, you can use conditional summation:
SELECT OGL.PACostCenter, vpt.LL6, sum((vpt.timeinseconds*1.0)/3600) [Hours],
sum(case when vpt.PAYCODENAME in ('519-H-Overtime 1.0', '519-H-Holiday OT 1.5',
'519-H-Overtime 1.5', '519-H-Overtime 2.0'
)
then (vpt.timeinseconds*1.0)/3600
else 0
end) as OvertimeHours,
sum(case when vpt.PAYCODENAME in ('519-H-Regular')
then (vpt.timeinseconds*1.0)/3600
else 0
end) as RegularHours,
FROM totals as vpt
INNER JOIN OracleLookup OGL on vpt.LL6 = OGL.OracleCostCenter COLLATE SQL_Latin1_General_CP1_CI_AI
WHERE vpt.DATE BETWEEN @StartDate AND @EndDate
AND vpt.PAYCODENAME in ('519-H-Overtime 1.0',
'519-H-Holiday OT 1.5',
'519-H-Overtime 1.5',
'519-H-Overtime 2.0',
'519-H-Regular')
GROUP BY OGL.PayrollAccount, vpt.LL6
ORDER BY OGL.PayrollAccount, vpt.LL6;