@Just-Lisa-Now- Thanks for your comments.

He cannot produce the IRS website with the purported IRS suggestion but sent me this link https://finance.zacks.com/use-k1-form-taxes-1804.html that he said support his aggregation rules on multiple K-1s reporting. I told him nowhere in the article suggested the idea.

I think this is one of the moment that I need to inform TP that we cannot continue with the preparation of the return without properly reporting multiple K-1s. Any comments?