awk 'function get(a,b,array1){array1[a]=a in array1?array1[a]"/"b:b} FNR==NR{A[$1]=$2;B[$1]=$3;S[++i]=$1;next} FNR!=NR && FNR>1{get($1,$2,A);get($1,$3,B)} END{for(j=1;j<=i;j++){print S[j], A[S[j]],B[S[j]]}}' *.txt

awk 'function get(a,b,array1){array1[a]=a in array1?array1[a]"/"b:b} FNR==NR{A[$1]=$2;B[$1]=$3;S[++i]=$1;next} FNR!=NR && FNR>1{get($1,$2,A);get($1,$3,B)} END{for(j=1;j<=i;j++){print S[j], A[S[j]],B[S[j]]}}'  a.txt  b.txt  c.txt

Name 9/1 9/2
X 1/13/25 7/19/31
y 2/14/26 8/20/32
z 3/15/27 9/21/33
a 4/16/28 10/22/34
b 5/17/29 11/23/35
c 6/18/30 12/24/36

awk 'function get(a,b,array1){
				array1[a]=a in array1?array1[a]"/"b:b
		             } 
     FNR==NR                 {
				A[$1]=$2;
				B[$1]=$3;
				S[++i]=$1;
				next
                             } 
     FNR!=NR && FNR>1        {
				get($1,$2,A);
				get($1,$3,B)
			     } 
     END                     {
				for(j=1;j<=i;j++){
							print S[j], A[S[j]],B[S[j]]
						 }
                             }
    ' *.txt