That is a pretty good strategy.
The other thing you might try is to “Y” off the Audio-In jack on the soundbar. You can get a little Y-cable on Amazon; just have to know what ends to get. If the input is 3.5mm headphone jack style, then you just need a Y-cable with 2 females and 1 male, and then use the 3.5-to-3.5 cable that came with the TV Connector. It did have a 3.5-to-3.5, right?
If you do this you’ll probably be able to keep your ambient sound on. I often run this way and I find that the TV connector has very little latency so there’s no echo effect for me listening both through the Marvels and through ambient sound. For me, if fills out the low frequencies.