Simplify the following text for a Grade 11 native English-speaking person.
Original: During his tenure , the Philharmonic instituted a number of then-revolutionary ideas , including the creation of the Los Angeles Philharmonic Chamber Music Society and the Los Angeles Philharmonic New Music Group and its `` Green Umbrella '' concerts ; both of these adjunct groups were composed of the orchestra 's musicians but offered performance series which were separate and distinct from traditional Philharmonic concerts .
Simplified: He had some new ideas , including starting the Los Angeles Philharmonic Chamber Music Society and the Los Angeles Philharmonic New Music Group . Both these groups had musicians from the large symphony orchestra in them .