The transfer function solution for your circuit is the following KCL result:
$$\frac{s\,R_2\left(C_1 + C_2\right) + 1}{s^2\,C_1\,C_2\,R_1\,R_2 + s\left(C_1\,R_2 + C_2\,R_1 + C_2\,R_2\right) + 1}$$
It's obvious from the above that \$T_1= R_2\left(C_1 + C_2\right)\$. Find the roots for the denominator using the quadratic equation to get \$T_2\$ and \$T_3\$. I'm sure you can handle the algebra.
That's all there is to it. Given any one value, the other three can be found. There are a few more interesting ratios to find. But they aren't necessarily important. Just interesting.
