@Straticah On a typical vintage synth there would be 2 typical scenarios.
One envelope - you can select if its for both filter and vca and if you would want the volume to be unaffected you would set the "volume/vca" to gate mode.
Then the "volume" is just on and off and the envelope shapes the filter but not the volume.
2 Envelopes , one for VCA and one for filter , which would give you what you have now.
So to have the second envelope no affect the first one , you would just not use a second one and use the first one for both OR, have a GATE setting where the VCA is on/off and the filter envelope takes care of things ,BUT then when you let go of the key there is no release.