=ПСТР($A3;ПОИСК(СЦЕПИТЬ(B$1;":");$A3;ПОИСК(B$1;$A3))+ДЛСТР(B$1)+1;ПОИСК(";";$A3;ПОИСК(СЦЕПИТЬ(B$1;":");$A3))-ПОИСК(":";$A3;ПОИСК(СЦЕПИТЬ(B$1;":");$A3))-1)

=ЛЕВБ(ПСТР($A3&";";ПОИСК(B$2;$A3)+ДЛСТР(B$2)+1;20);ПОИСК(";";ПСТР($A3&";";ПОИСК(B$2;$A3)+ДЛСТР(B$2)+1;20))-1)

=СЖПРОБЕЛЫ(ЛЕВБ(ПОДСТАВИТЬ(ПСТР($A3;ПОИСК(B$2;$A3)+ДЛСТР(B$2)+1;20);";";ПОВТОР(" ";50));50))

Function FindName(r1 As Range, r2 As Range) As String
Dim j As Long
    j = Application.WorksheetFunction.Find(r2.Value, r1.Value)
    FindName = Split(Mid$(r1.Value, j + Len(r2.Value) + 1), ";")(0)
End Function

=FindName($A3;B$2)