[Users] How to check destination set after branch_route?

Hello, I am trying to filter out requests going to some IPs. So, I have a branch_route block where I drop the branches that go to the IPs I want to block. After the t_on_branch command I call t_relay. This works fine if the callee has registered with at least one "good" IP. If the callee has registered with only one IP which I want to block then there is only one branch that is getting droped. The following t_relay results in a 500 Server error. Is there a way to check if all branches have been dropped? I tried using isdsturiset() but it did not work. Even if there is only one branch and this branch has been dropped, isdsturiset() returns true. Is this correct or am I wrong somewhere? thank you for any help George Disclaimer The information in this e-mail and any attachments is confidential. It is intended solely for the attention and use of the named addressee(s). If you are not the intended recipient, or person responsible for delivering this information to the intended recipient, please notify the sender immediately. Unless you are the intended recipient or his/her representative you are not authorized to, and must not, read, copy, distribute, use or retain this message or any part of it. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses.