Finding transfer function from a system of linear equation (5eqs and 5unknowns)

I want to get the transfer function G(s)=U1/Ub

I attached the laplace of my math model which is a linear system of equations (5 equations& 5 unknowns).

I want to know how i can use matlab to;

1. re-arrange each equations in terms of Ub, U1, U2 U3, and U4?
2. After re-arranging how i can target each of varibles Ub, U1, U2, U3, U4 in the re-arranged equations and replace them with another equation of my choice ?

The reason is that doing this by hand is tedious process so I appreciate if you show me the code.

[MN]

my end goal is to get transfer functions; U1/Ub, U2/Ub, U3/Ub, and U4/Ub from the math model (5 equations)