As far as I know there’s not a way to do that. But I have a handy tool to link you to: New Tool (2.7 & 2.8): Fractional Notes
This makes it easy to do triplets (and other fractional rhythms) when using a lpb that’s not a multiple of 3. A lot of people just use 12, but I prefer to use 16 and just use the fractional notes tool when I need triplets.