Quotient group for matrix groups?

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Is there a way to create a quotient group for groups in the class MatrixGroup? The following use of .quotient(H) gives a NotImplementedError.

p=3
F=FiniteField(p)
t1=matrix(F,3,[1,0,1,0,1,0,0,0,1])
t2=matrix(F,3,[1,0,0,0,1,1,0,0,1])
t3=matrix(F,3,[1,0,0,0,1,0,0,1,1])
G=MatrixGroup([t1,t2,t3])
opts=[]
for a in G:
     h=a*t1*a^-1
     if h not in opts:
          opts.append(h)
H=G.subgroup(opts)
print(H.order())
Q=G.quotient(H)