Answer:
They each have a reading that repeats a sound.
支 SHI, sasa(eru) - branch, support
包 HOU, tsutsu(mu) - wrap
縮 SHUKU, chiji(maru), chiji(meru), chiji(rasu), chiji(reru) - shrink, contract, make curly
桃 TOU, momo - peach
叩 KOU, tata(ku), hika(eru) - hit, strike