The combination will be a bit much for the Eros to drive. This would likely manifest as some additional distortion.
I was about to author some nutty mod to the Submissive to switch out the attenuator depending on what you're doing, but there are two obvious solutions.
1. Use the Mainline as a preamp. I know, it sounds weird, but we have done it and it works nicely (not quite as nicely as a BeePre, but still a great preamp). A 1/4" to RCA cable will let you listen to this in a quick and dirty fashion.
2. The Mainline has a Submissive built into it, so you could add a set of outputs from the attenuator to a pair of RCA jacks to drive the Paramounts.