Starting task B immediately after A

My issue is that I’m unable to force omni plan to always start task B immediately after task A. I’m making a product that will spoil if it sits at the end of task A, and need it to move on to B as soon as it is finished. I have split the process into two separate tasks because task A and B used different resources.

Even when I make task A alap, and task B asap there is still a hugh gap between A and B in some cases.