Sub-agents always read instructions from claude.md - not always good

When Opus starts some exploration and runs his agents, they automatically follow all instructions in claude.md. However that's not necessarily good - i have a lot of instructions there, and they don't need to do everything (like read every single piece of documentation). The question is, can I somehow add instruction in claude.md that would be picked up specifically by these sub-agents that are spawned (for instance "if you are xyz, then only do abc, ignore the rest of instructions")? How to discern them reliably?