Anything is possible, it often takes more$ and wit.
Problem: output -> input1 and input2. if input1 is analog and input2 is digital or viceversa, you will get echos.
Since everything eventually end up as analog, then what you want to do to solve the above problem is, convert audio to analog, THEN split the signal (D to A conversion introduces delay). How exactly do you do that depends on what kind of input are available from your two inputs.
If both of your inputs are digital and can accept Optical in, use an optical splitter and you hope the delay between DAC1 and DAC2 is close enough to not get the echo. DAC=Digital to Analog Converter.
You can do it by splitting the same output and connecting both but don't expect it to work well.
The speakers and soundbar will interfere with each other and may sound worse than when used separately.
If you can set up the PC for 3.0 then you could use the soundbar as a center channel.