I don't know, but I think it should heavily depend on the situation, player placement, and RP circumstances.
A Jedi closely escorting his two non-Jedi friends through a hallway would likely not have much trouble parrying multiple blaster bolts to save them.
Gunslinger Joe repeatedly shoving his friends aside out of the way of blaster bolts in the same hallway would be ridiculous. Especially if he's on the other side in RP, blasting away at stormtroopers.
Someone large like a Hutt could conceivably shield all of his friends with his great mass, but that begs the question of how he himself is dodging the hits instead of sacrificially taking damage.