Conditional execution of jobs is normally done via scheduler. LSF for example allows for such conditional job execution.
You have always the option to wrap a job into a macro using job pre- and post-code.
In the pre-code section you have then something like "%macro MyMacro; %if <expression> %then %do;", and in the post-code you have something like "%end; %mend; %MyMacro;"
You can do the same in the pre- and post-code of any node as well. If you want several nodes wrapped into such a macro then I probably would use separate user written code nodes to define the macro for clarity. But you could also just use the pre-code of the first node and the post-code of the last node to set this up.
Not sure what happens if you feed an empty table to the teradata table loader. I would assume if the table is empty then no loading happens so may be you even don't have to care about conditional processing (but of course if it's a replace load then the target table would still get truncated).
