Is there a way to auto-populate blank cells with a center-aligned dash?

I’m in the process of putting together a table, and not every row is going to need to utilize every column. What I’m looking to do is create a table that automatically populates blank cells with a dash. The issue is, I want the rest of the data in the table to be aligned to the left, but I want the dashes to be centered. Is there a way to do this? I’ve tried messing with some =IF and ISBLANK formulas but I can’t seem to get it correct.

For context I am creating a phylogenetic table and for example, many orders have infraorders or superorders, but many others do not. So it’s text-based data, if that matters.