Setting up animation blueprint transition

I am setting up an animation blueprint for my player character with many start and stop animations and blendspaces. I am trying to obtain the seamless possible transitions between the various states/animations.

When transitioning from animation A to animation B, I am using the node “Animation A - current time (ratio)” to set up the start of the transition in the animation A.

This works rather well but the transition is not really seamless. This is due to the fact that the transition always plays the animation B from the beginning (the start frame of the animation B is always 0). Thus if the transition is set to last 0.2s (the default duration), the B animation plays from frame 0 to frame 6 during the transition.

The only way to get the perfect transition would be to also set up a start frame in the animation B. Thus for example, the B animation would start the transition at frame 20 and play from frame 20 to frame 26 during the transition.

How can I do this?

Thanks a lot.