Insert new row that automatically copies select values from above row

[aikia]

Hi,

I'm creating a "form" for non-Excel people to fill in certain values. I would like to allow them to insert new rows but make sure that the new rows copy over data from above rows.

For example: columns 1 and 2 are pre-populated with a list of names, tshirt size is blank but users have a dropdown to select values

First Name Last Name Tshirt Size
Jane Doe [Dropdown]
John Smith [Dropdown]

Users can insert new rows - the new rows would have the First Name & Last Name copied from the above row, while the Tshirt Size column would be blank (awaiting user selection).

First Name Last Name Tshirt Size
Jane Doe [Dropdown]
Jane Doe [Dropdown]
John Smith [Dropdown]

This would just an example data set, what I'm actually asking is a lot more complex.

I need to do this so that when users create new rows, certain columns of data are copied over to allow for filtering.

Additional functionality: Is it possible to do this and have new rows inserted that are automatically "grouped" with the row above?

Thanks in advance!