Easel only support two stage carve, to use three you can fudge it by copying the project as a new work piece and utilize a third tool there.
However, to cut down carve time, at least for the roughing part - increasing step over from Easel default 40% to like 75-80% will help.
Experimenting with your tool and Xcarve to see what it comfortably can take, and use that data to reduce carve time may be worth the hassle. Easel carve rates are conservative and safe.
I´d try to bump up the feed rate from 40 to 55ish assuming a 2flute bit for the 1/8. Depth per pass also for 1/4 and 1/8 bit.