From your description it sounds like you are using the L&R front preouts to feed to the subwoofers. You don't describe how you feed the subwoofers to your Rotel amp. I believe you have two choices.
1) Use a Y splitter, like gonk suggested, connected to the 1050's sub out to feed the subwoofers and feed the Rotel from l&r front preouts on the 1050. Depending upon how low your fronts go, you should probably configure the front speakers as small. I run in this configuration with a single sub and it works well especially for Home Theater usage.
2) Configure the 1050 so the fronts speakers are large, run the 1050 front outs to the subs as you described and run the sub high frequency preouts into the Rotel. This will be excellent for 2 channels but I have a feeling it will not work as well for home theater applications.
There may be a way to get the 1050 to feed the LFE to the fronts but I am not aware of how to do this. A little manual reading may suggest a method.
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Living Room 24x18 open 1/2 flight up to a raised dining room/hall 24x12
Outlaw 976 pre-pro running 5.1 system
Outlaw 750 for Artison Masterpiece LCR and 2 NHT SuperZeros rears
Velodyne Servo FX-1200
LG OLED65C8PUA via HDMI2 to/from 976 HDMI ARC
Roku Ultra
Samsung BD-D5500 BluRay
Amazon FireStick 4K to 976 Aux HDMI input for Amazon Music Ultra