What if some of them are slaves? Will they properly sync at 1/8000 along with the radio triggered ones?
In order to get HSS with a remote off-camera flash, you need three things:
A camera body that performs HSS. For example, the Nikon D3x00 and D5x00 bodies cannot perform FP/HSS, so no matter what flashes or triggering system you're using, there's no chance of getting high-speed sync. And your camera body has to be capable of 1/8000s to get that shutter speed with flash. Most camera bodies max out at slower speeds.
Flashes that are compatible with the camera body that can perform HSS. That is, if you shoot Nikon, you need a flash that can perform Nikon's FP flash. If you shoot Canon, you need a flash that's compatible with Canon's HSS communication. If you're using a manual-only flash, like the YN-560III, you're out of luck.
A system-compatible triggering system that can communicate HSS/FP. If your radio triggers do not communicate HSS, it won't work. If you're using a manual-only triggering system such as PC sync cable, Yongnuo RF-603II, most add-on optical slaves, etc. it won't work. If you're using a hotshoe-to-hotshoe TTL cable, it will. If you're using TTL/HSS-capable radio triggers (e.g., YN-622, RadioPopper PX, Phottix Odins, etc. etc.), or the built-in wireless TTL-compatible system (Nikon's CLS, Canon's RT or optical slaving systems) with an HSS-capable master (e.g., Canon's pop-up flashes with masters cannot do HSS), then it will work.
Keep in mind, however, that HSS robs you of power (roughly two stops) and that the faster your shutter speed is, the more diminishing your returns are going to be.
If each flash/speedlite works with HSS individually they should work together. If a flash/speedlite is being triggered with something other than E-TTL then HSS on that device won't work and you'll end up with a dark band. Even if the device does support E-TTL it's not guaranteed to be HSS compatible.