Training for a race series

Hi all. My main competitive racing is in the Spartan National Series. I started using Athletica last year, and I programmed my race dates in and selected the corresponding run distance as the race distance. I managed strength myself, as there is no OCR or similar plan in Athletica (Hyrox is there now, but the run portion is not quite the same).

Last season, the races were Beast (21km), Super (10km), and Beast (21km) - each separated by 4-6 weeks, so Athletica started me out with a half-marathon training plan, switched to a 10km in the middle, and back to a half-marathon at the end.

This season, the first race is a Super (10km) and the next two are Beasts (21km). If I just drop these in like I did last year, I end up with a 10km plan up until the first race and then a half-marathon plan between the subsequent races (6 weeks and 8 weeks this time).

My concern here is that I won’t end up with enough volume on the 10km plan, so my second and third races will suffer. Is there a better way to go about programming for this type of scenario?

Thanks!