No, You Cannot Bi-Amp

The designers of these speakers do not believe that bi-amping is superior to the as designed implementation.
The .7 maggies have a series crossover that they feel superior to any form of biamping. Wilson from the start has always felt that a single amp gives the best overall sound. I have tried bi-amping my 3.6's but have always gone back to a single amp

Take the money you save on extra amps, cables, and jumpers and buy a nicer amp, probably with more power so you don't give up any dynamic range.

In my mind biamping is a 'teenage' phenomenon.
If one is good, two MUST be better.
Yeah a few folks are able, with effort to make it work for themselves.
In general it is a waste of time, if as much effort was made to have one amp work well.
The worst side of it is all the folks who know nothing about it wanting to do it as if it is some easy magic panacea.. Gee I could biamp,,Cool!.... NOT.

Sonic benefits:

Transparency
Dynamic Headroom is not jeopardised by either descrepancies of amplifiers or decreased input amplification impedance
Tonal balance

Negatives:

1. 2 cheaper lower powered amps can have more power than one nicer more pricey amp so there are limitation on available options that should IMHO be present in complexed speakers
2. If two amps are absolutely identical, the benefits could be identical to a single amp only with increased power.
3. Y-connector on preamp output may be necessary that decreases an input impedance of amplification again limiting the dynamic headroom.

Ahendler's comment is right on target. The series crossover is not amenable to biamping. My opinion of the crossover in the 3.7's is that is a pretty significant improvement over the stock crossover in the 3.6. I drive mine with Cary 500 MB's, which delivers sufficient current to drive the speakers without biamping. I have heard neither the 20.1's or the 20.7's so I can't comment on those two. Let your ears be the judge.