二欄改一欄 相同相聚緊接另一欄 (13714)

E2{=IFERROR(INDIRECT(TEXT(RIGHT(SMALL(MATCH(B$2:B$11,B:B,)*10^5+ROW($2:$11)/1%+{2,3}*10001,ROW(A1)),4),"!R0C00"),),"")

另解{=INDIRECT(TEXT(SMALL(IF({1,0},MATCH(B$2:B19&"",B:B&"",),ROW($2:19))/1%+{2,3},ROW(A1)),"!r0c00"),)&""