Merge 2 index based off fields and not rows

Hi Opensearch team,

I’m looking to merge 2 index’s based off unique ID which is same across both the index and the desired index should look like,

Index 1
ID, Email, Fax

Index 2
ID, Email, Fax

Now the merged Index should be,
Index 3
ID, Index1_Email, Index2_Email, Index1_Fax, Index2_ Fax

Hence the merge has taken place by field and not rows.

Appreciate your input’s.