The group wants to remove prosecutorial authority from the chain of command.
A public hearing is planned for April 16 and the court-marshal trial is set for May 7-22.
Hollenbeck was granted a retrial after an court determined the verdict was flawed because of a possibly biased juror.
The schools received a total of 149 sexual-assault reports, up from 117 received the prior year.
Jacob Blair Scott received a Purple Heart in 2011 for injuries he sustained while deployed in Iraq.
The two-star, who retired from the Army in 2005, was arrested Dec. 7, 2018.
The National Guard Bureau in December announced it had uncovered multiple shortcomings in the Wisconsin Guard's protocols.
Illinois Sens. Dick Durbin and Tammy Duckworth sent a letter to Army Secretary Ryan McCarthy requesting an investigation.
The Wisconsin Guard's top commander, Adj. Gen. Donald Dunbar, resigned at Gov. Tony Evers' request.
Court documents called the 2016 incident "an alcohol-fueled sexual encounter."