Not that I know of. Its either one or the other. You can have options on some sound devices for which headphone/speaker jacks are or aren't active but you can only have one default audio playback device at a time and thus everything gets routed through that device.
My Computer
Computer type
PC/Desktop
Computer Manufacturer/Model Number
My Own Build
OS
Windows 10 64 bit
CPU
Intel i7 6700K
Motherboard
ASUS ROG Maximus VIII Hero
Memory
16GB Corsair Dominator
Graphics Card(s)
Intel CPU Graphics
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RealTek
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27" Dell S2719dgf
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2560X1440
Hard Drives
1 TB Samsung 850 EVO SSD for Win 10 Pro
500GB Samsung 850 EVO SSD for Win 10 Insider
2 TB drive for backup
PSU
EVGA Supernova 750G2
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BeQuiet Silent Base 600
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Deepcool Captain 120EX
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Microsoft Wireless 2000
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Microsoft wireless
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Other Info
Cakewalk (Sonar) by BandLab and Studio One 4.1 Pro recording studio software. MOTU 896Mk3 Hybrid recording interface, Frontier Tranzport wireless control unit, Behringer X-Touch Control Surface.
Five USB connected optical drives for CD Audio production using Nero BurningROM
Right.
Once stereo jack is plugged the sound is routed through it, the sensor is giving signal to the sound driver to terminate internal speakers. The only way you can do is split it to a head set and another (external) speaker system.
Use this $2 splitter.