Long story short NO
Let me guess you want to run your dash, door and rear speakers on 1 amp.
They make 6 channel amps.
You can use a 4 channel amp on all 6 speakers IF the 4 120 watt ones are the same size. then you can run 2 per channel and then you can run the 150 watt ones at 1 per channel.
This is the most info I can give you without knowing your vehicle and the brands/sizes of speakers and amp you plan on using.