Bi-amping with integrated

If I wanted to try bi-amping some speakers using a Cronus Magnum for mids and/or highs and tbd 2 channel or mono blocks for lows, is that possible?
It has a variable output, so if your speakers have dual binding posts, then yes.
To actively bi-amp an integrated, requires being able to separate the preamp from the power amp, and installing an active crossover between. The Cronus doesn’t have a Pre-Out/Main-In facility. It does have a variable output(could be used for a woofer amp), but- that won’t allow you to filter lows from the main amp. A Tape loop would have worked, for inserting a crossover, also. You could get away with connecting an amp of identical power/gain/sensitivity as the Cronus, to the variable output. Both amps would be handling full spectrum and the speaker system’s internal crossover would be doing the dividing. Not ideal!
I've used a power amp to drive the bass, or bottom binding posts while using the int to drive the top and many times it's worked with excellent results, but a few years ago I used a power amp with identical power ratings at 8 and 4 ohms as the int and the gain was so different that the bass was overdriven causing a very unnatural sound. There was another case where I had 2 different power amps and a pre and I put the amp with double the power rating on the bass and the results were very musical. 
Make sure the gain as well as power output is close or you will have an imbalance and unnatural sound.