No. The YN-568EX cannot act as an optical or radio master. The YN-568EXII (Canon only at the time of this posting) can act as an optical TTL master, but has no radio transmitter capability built-in.

If you need TTL on-camera fill flash, your best bet, if you're a Canon shooter, would be to use a YN-622C on-camera, and to put the YN-568EX on its pass-through hotshoe, and use the camera menus to control the remote YN‑568EX via another YN-622C as a receiver on its hotshoe.

See also: the TOYUG.

If, however, you're a Nikon shooter, sandwiching a YN-622N will not be a great solution for you, because there is no control of remote flashes from the camera menu, and you'll have to use those, um, less-than-intuitive buttons and LEDs on the YN-622N to change the power setting on the remote flash. It will work, but it's a pain. Your best bet is probably to find a Nikon CLS commander speedlight of some kind, such as an SB-700, and put that on the passthrough shoe, and then you can control the remote lights via the SB-700's menus.

See also: Flash Havoc's report on the YN-622N triggers and LightingRumors description of how to set remote power with a YN-622N.