How to exctract specific elements from .txt file?

I have one .txt file with 10 columns. In columns 5,6 & the same elements are included.

Considering that, I would like to extract from this input all the rows that include same elements in columns 5,6 & 8 that might be repeated more than 2 times in the table array.

I tried unique and ismember commands, but I cannot syntax the suitable command.

For example:

Input :

4  65  7.5  MGK  4  5  66  MARKUS  46.63641  65 

11  26  5  LEON  78  93  88  LUTHER  50.3554  5 

6  2  6.5  NDSGN  4  5  77  MAKRUS  59.67196  3 

6  8  4.5  ANGEL  24  23  99  JOHN  31.87303  -1 

6  2  6.5  NDSGN  56  89  100  ALEX  100  0 

9  6  4  MARY  56  89  100  ALEX  2  200 

Output file:

4  65  7.5  MGK  4  5  66  MARKUS  46.63641  65 

6  2  6.5  NDSGN  4  5  77  MAKRUS  59.67196  3 

6  2  6.5  NDSGN  56  89  100  ALEX  100  0 

9  6  4  MARY  56  89  100  ALEX  2  200 

Could you please help me?

Answer 1

[dpb]

d=  [' 4;  65;  7.5; MGK  ;  4;   5;  66;  MARKUS;  46.63641;  65'
     '11;  26;  5  ; LEON ; 78;  93;  88;  LUTHER;  50.3554 ;   5'
     ' 6;   2;  6.5; NDSGN;  4;   5;  77;  MAKRUS;  59.67196;   3'
     ' 6;   8;  4.5; ANGEL; 24;  23;  99;  JOHN ;   31.87303;  -1'
     ' 6;   2;  6.5; NDSGN; 56;  89;  100;  ALEX;  100      ;   0' 
     ' 9;   6;  4  ; MARY ; 56;  89;  100;  ALEX;    2      ; 200'];
t=array2table(strtrim(split(string(d),';')));
t=convertvars(t,[1:3 5:7 9:10],'double')

t = 6×10 table
    Var1    Var2    Var3     Var4      Var5    Var6    Var7      Var8       Var9     Var10
    ____    ____    ____    _______    ____    ____    ____    ________    ______    _____

      4      65     7.5     "MGK"        4       5      66     "MARKUS"    46.636      65 
     11      26       5     "LEON"      78      93      88     "LUTHER"    50.355       5 
      6       2     6.5     "NDSGN"      4       5      77     "MAKRUS"    59.672       3 
      6       8     4.5     "ANGEL"     24      23      99     "JOHN"      31.873      -1 
      6       2     6.5     "NDSGN"     56      89     100     "ALEX"         100       0 
      9       6       4     "MARY"      56      89     100     "ALEX"           2     200 

[g,idx]=findgroups(t(:,[5 6]));
n=histc(g,unique(g));
[ia,ib]=ismember(g,find(n>1));
tU=t(find(ib),:)

tU = 4×10 table
    Var1    Var2    Var3     Var4      Var5    Var6    Var7      Var8       Var9     Var10
    ____    ____    ____    _______    ____    ____    ____    ________    ______    _____

     4       65     7.5     "MGK"        4       5      66     "MARKUS"    46.636      65 
     6        2     6.5     "NDSGN"      4       5      77     "MAKRUS"    59.672       3 
     6        2     6.5     "NDSGN"     56      89     100     "ALEX"         100       0 
     9        6       4     "MARY"      56      89     100     "ALEX"           2     200 

NOTA BENE:

1. The description is inconsistent; none are extant in the sample dataset with >2 repeats so used 2 as the lower count
2. Used only 5&6 as the grouping variables even though one place says "5,6 & 8*' because
3. "MARKUS" and "MAKRUS" don't match in original dataset; not clear if this is just a typo or supposed to be real. If just a typo, if corrected, then 5,6,&8 would also produce two sets in the result.