Can we convert a free text country field into a drop list of country on Legislation info?

On Hire an Employee Screen, under the Legislative Info section, there is a field called Country which return the country name of the input legal entity, which was previously input in the section "when and why".

The country field is currently in view only format and we found that it can be set up into free text format via page composer. However we would like to add a drop down list of all country to this country field.

Is this implementation feasible?