Grid of remarks in Item Manager Layout

Summary:

Can we have a grid of remarks (two levels deep) in Item Manager Layout

Content (please ensure you mask any confidential information):

Client wants to have a lot of additional info on Item master. And these info should be entered in a grid (matrix) with columns defined but rows undefined. It can look like below.
Remark 1, Remark 1a, Remark 1b, Remark 1c;

Remark 2, Remark 2a, Remark 2b, Remark 2c;

Remark 3, Remark 3a, Remark 3b, Remark 3c;

For each row, first Remark can appear to be primary key for the entire record in that row

For example,

Material (Remark )	Color (