How to count joined rows in a table as one?

Question

Google Sheets

There are 10 rows in the table. I combine them in 5 by 2, for a total of 5 wider lines, each consisting of 2 combined. By setting the formula in the first such merged cell, I need to "pull" the result to the rest. But here's the problem: when stretching down to the rest of the cells, their number does not change A1, A2, A3, but with a step - A1, A3, A5. This is a problem, because other data in the adjacent table still refers to A1, A2, A3. Can you tell me how to make the merged cells have consecutive numbering?
Thank you.