How did you wire them? More information would be helpful.
That said, you have a couple of options.
That receiver can natively run two separate sets of stereo speakers. Hook one set to the jacks marked Front A and the other to the jacks marked Front B in small print. Use the Speaker button on the front to switch between them. It may or may not allow you to drive them both at the same time.
Second, if you don't want to also use the receiver for home theater/surround sound, and your receiver has an 'all stereo' or '7 channel stereo' mode or something similar, it can effectively run 3 sets of speakers, albeit with no individual control. You could wire volume controls in line to each set of speakers to get your own manual control. Wire as above and add a third set to the Surround jacks and then choose the All Stereo mode.
Beyond this, things get a bit more complicated, as you need to add a speaker control box. This seems simple, but realize that most of these wire in the additional speakers in parallel, which reduces the load seen by the amplifier, and can damage your equipment. These typically recommend an amplifier that can drive 4 ohms which yours cannot, so research carefully.
Another option is to do the above, and add an impedance matching volume control at each set of speakers, which would allow you to tailor the load to work for your particular components. Again, tread carefully.