How can i set the Transport Delay Block's initial output as the other block's first output rather than constant

How can i set the Transport Delay Block's initial output as the other block's first output rather than constant?

For example, if i set the initial output as zero, the Transport Delay block wil exactly start with zero. However, i need the initial output is the other block's first output, and it is a variable value (not the same each simulation). How i can do that?

It will be appreciated if someone have good suggestions. Thanks!