Group name and mergge properiatory firm with pvt ltd firm

Hello,

This is Navaneethan. I own one properiatory firm ( CHEMZEST ENTERPRISES) from 2012. And we have started another PVT company  (CHEMZEST TECHNOPRODUCTS PVT LTD ) and my share is 50%

.I would like use properiatory firm  credentials for the PVT ltd as we are separating few products to PVT LTD.

Can we bring both company together with single group name?

Whats the documents needed and procedure to follow?

Thanks for your support in advance.