write to segment (multiple locations) of memory

I think what I need is simpler than a "many port RAM".

I don't need to read multiple values in parallel. One at a time is fine.

I don't want to write different values in parallel.

I want to write one value in multiple locations (segment) by selecting the respective memory words and putting one data value on the data lines.

If I do it with registers, it's bigger in size because it gives me access to every bit of every word in parallel. I don't need that. Just write a value in multiple locations.