How to add same items into subgrid of multiple entities

Hi folks,

I want to add the same items into many entities' subgrids and out of the box function of CRM does not really support this I believe.

Illustrating example:

I want to add some Competitors records in the Competitor subgrid of Lead entity:

But I want to add the same Competitors for many other lead entities

Is there any idea to achieve this? Any ideas will be much appreciated!