Effects with modifiers

It would be interesting to have the possibility of having modifiers, applied through effects.
As with Savage Worlds, global effects and situational effects.
Example: The characters are fighting in a cave full of stalagmites (difficult terrain) with low lighting.
These would be global effects that would affect everyone.
One of the characters decides to hide behind one of the cover stalagmites (this would be a situational effect), while another decice to lie down to have better support for his weapon (this would also be a situational effect) but of position.
Each of these effects would affect attack rolls, being attacked, active defense and could be mitigated through advantages and accessories.