I'm not sure what the proper term is for this so I've struggled to find answers.

I want to either

a) add data to two tables at the same time, without changing any existing queries. Something that can be done in PHPMyAdmin hopefully. As if there's a setting to duplicate any new entries to TableA into TableB also.

b) "symlink" a table to another name, so one table/name points to another table. Data goes into TableA but requesting data from TableB which is "symlinked" gives you the TableA data.

Are either of those ideas possible? Or a similar alternative.

You want to create a view.

Indeed I do, works exactly how I want it to. Thanks Peter.