Currently with NeoLoad 3.2.xx, the only way to achieve that is to insert your transactions within a loop or while logical action.

Your virtual user will login, iterate a multiple times and logout.

In our next version 4.0 coming soon, this behavior will be the default one. You will have an Init, Actions and End containers. The Init and End container will only be played once whereas you can iterate on the Actions one.

That is to say that if you put your login container inside Init and logout container inside End, the login and logout will only happen once.