A family of Microsoft word processing software products for creating web, email, and print documents.
You could try pasting the data into Word as a freestanding column (a separate table). The select that column and insert it in the existing table by selecting the column of end-of-row markers and pasting.
Alternatively, you can convert the existing table to text, insert the Excel data as paragraph text (or as a table and convert to text). Use Replace to replace the paragraph break at the end of each line in the first group with tab and paragraph mark. Then use Alt+click to select the second set of data as a column and drag it up to the right of the existing column. Then select the whole and convert to a table, separating at tabs.