You'll have to tell me if I got this ARRAY FORMULA right:
R3: =STDEV.P(IF(ISNUMBER(MATCH(ROW($A$2:$A$31),LARGE((($A$2:$A$31=$N3)+ ($A$2:$A$31=$O3)+($A$2:$A$31=$P3))*ROW($A$2:$A$31), 
ROW(INDIRECT("1:"&SUM(COUNTIF($A$2:$A$31, $N$3:$O$3))))),0)),$C$2:$L$31))
Copy R3 and paste into R4:R5

Does that help?