I would like to know if it is possible to define a homomorphism between a group algebra over the rationals and a matrix space over the rationals.

I have
```
sage: S3 = SymmetricGroup(3)
sage: QG=GroupAlgebra(S3, QQ)
sage: QG.gens()
Finite family {(1,2,3): (1,2,3), (1,2): (1,2)}
sage: M_3 = MatrixSpace(QQ, 2)
sage: ma = matrix([[0,-1],[1,-1]])
sage: mb = matrix([[1,-1],[0,-1]])
```

Now I would like to map each generator of QG to a matrix. In this case I would like to map (1,2,3) to ma and (1,2) to mb and use that to define a homomorphism. But everything I tried didn't work.