If you have a receiver that can handle 780 watts and 4 speakers that put out 900 watts max total could it work

Answer 1

Short answer – yes your speakers and receiver will work together.

Long answer ~

The manufactures marketing has confused you – as intended.

Your 780 watt receiver probably outputs about 130 watts per channel into 8 ohms (6 X 130 = 780) – I’m guessing it’s a 6 channel receiver.

Your 4 speakers can each handle 225 watts (4 X 225 = 900).

The reality is speakers don’t blow up from to much power – they self destruct from the distortion of to little power.

Enjoy your system!