How to set a fixed table template in MS Word?

Question

Word

The essence of the problem is as follows: smarty is used to generate reports in php. It generates reports in RTF format, but the task appears to generate such a table:

Where the number of rows must be dynamic, and the right column must always be the 1st combined.
When you try to add columns in the Word (I think the template zador will act according to the same algorithm), then the following happens:

I.e. a line I don't need is added in the right column. Is it possible to somehow set that when adding rows, the right column remains in the 1st row.
For example, I display other tables like this:

Thanks in advance to the collective mind.