I would click the map button in the slice Osc playback section to get them mapped to separate key groups, then select all the key groups by click and dragging across the key mapping area, when they change color all edits (to the Amp. Env for instance) will effect all selected samples/keygroups.
In List-view, you can always see which KG is selected and also do bulk selection via cmd+A (on Mac), or click on a layer and all KGs in that layer will get selected, or click on Program and all KGs in all layers will get selected (also works in Tree-view).
Your welcome, I’m glad you asked because I learned about the list view select all. It would be nice, however, to be able to right click for options from the list but it seems only possible from the graphic display in key mapping area.