Existence of transfer function

This is my system.

Is there a way to find a transfer function? I can’t help the YR(s) going inside B(s) without being sampled, and I think this is the problem. Any help?

You need to determine an expression for the samplers. Normally i would think that those are A/D converters, but they give $A(s)$ and in the variable $s$ it is implied (sort of) that is the laplace transform, and laplace transforms are used for continuos time systems, so the samplers T could also be just converting the signal into a piecewise constant signal, and that is a non linear operation.