Its only got one transmitter, so you can't send anything simultaneously.
You can however change what is sent every time it advertises. Hence send a different packet each time.
This has been discussed several time before on this forum, so if you need details of how do to it, your best option is to use the search feature in this forum.
As Roger explains you cannot transmit from one radio (= one chip) simultaneously. I guess you are asking if nRF5x can advertise on all 3 Adv. channels (37, 38, 39) during one adv. interval and the answer is YES. This is how Nordic stack (Soft Device) work by default in GAP Peripheral/Broadcaster modes, it emits 3 Adv. packets in short time (remember that it must to listen for short time window after every adv. Tx) so it appears that there are 3 "almost" simultaneous packets sent. But you can restrict adv. only to two or one from three adv. channels. If you are not using Nordic stack then you need to ask stack provider or write this yourself.
Btw. You can see this nicely on oscilloscope screenshot at this blog post (it looks like single peaks from the distance with exact period of adv. interval but you can see 3 Tx peaks when you zoom in;).
