Solutions for combining multiple sources for one ref column

Curious to hear of ways to do this, or if there is a sort of "gold standard". I have a column that I'd like to make a ref of two other tables. In other words, I'd like there to be a drop-down in this column where the user can select from the label values of two other tables. I realize one can easily combine lists inside a validif or suggested values formula, but in this case I need the values in the drop-down to automatically change whenever the source values (i.e. the label values in the other tables) change. A ref does this natively, but it seems quite clear that you must choose only one source table for a ref column. I suppose I could combine these lists with formulas outside of appsheet in my source tables (Google Sheets) or inside appsheet via actions or bots, to create one unified table my ref points to, but I wonder if there is a better way to handle this I haven't thought of? Thought to check with the community first.