An idea I had to represent the Slivers' ability to grant each other powers in Magic: the Gathering. As follows:
Sliver Collective Blast: Affects Others Perception Area (Sliver Sense) Enhanced Ranged Damage
Sliver Sense: Senses 3 (Extended Ranged Mental Detect Sliver Effects)
This way, a Sliver has the Sliver Sense power, and thus is affected by the Sliver Sense Perception Area Enhanced Trait (here I used Blast, but given the variety of Sliver-ness that exists, it could be just about anything). The fact that the Perception Area targets Sliver Sense keeps non-Slivers from getting access to the power.
"There are some who call me . . . Tim."