C2 =IFERROR(LOOKUP(,0/((A2=A$1:A1)*MMULT(LEN(","&B$1:B1&",")-LEN(SUBSTITUTE(","&B$1:B1&",",","&TRIM(MID(SUBSTITUTE(B2,",",REPT(" ",99)),COLUMN(A:Z)*99-98,99))&",",)),ROW($1:$26)^0)),ROW($1:1)),"")
D2 =IF(C2="","",LOOKUP(,0/(LEN(","&INDEX(B:B,C2)&",")-LEN(SUBSTITUTE(","&INDEX(B:B,C2)&",",","&TRIM(MID(SUBSTITUTE(B2,",",REPT(" ",99)),COLUMN(A:Z)*99-98,99))&",",))),TRIM(MID(SUBSTITUTE(B2,",",REPT(" ",99)),COLUMN(A:Z)*99-98,99))))