Problem:
I have a survey dataset which includes intra-household relationships. I had to subdivide household into tax-unit, which means I need to redefine the relationship matrices based on the new tax-unit grouping.

I am trying to select or subset multiple data frames with different number of columns. They all contain the same columns of interest, so I am trying to make them all contain the same columns so I can then append into one data frame. I am trying to be as elegant and efficient as possible, but my codes does not seem to be working. This is what I tried to do: