You can't separate it from the LightMix (you can do it from the Beauty, with a VirtualBeauty with bloom&glare unchecked), so what you can do is this -
- Add a bloom and glare render element
- Once rendered, save all to save out everything separately, including all the individual LightSelects
- Stack the LightSelects in post, using Linear Add in your software of choice. Carry out your LightMixing here, adjusting hue and intensity of the individual LightSelects
- Place the bloom & glare on top of this.
BUT do note that this will mean your bloom&glare is based on the single Beauty and will not account for the edits you make in the composite.
Also, what are you trying to achieve btw? Might be easier just to save the LightMix with b&g on, then turn it off and save it again, doesn't require re-rendering. You could then combine those in post, masking out the bloom & glare version to control b&g strength or use adjustment layers to tweak b&g colors. Or you could subtract b&g off version from b&g on version to end up with isolated bloom and glare, that should work too.