Perhaps increased suppression & worse suppression recovery if you're too far from the squad/SL? Maybe make it so that it increases proportionally with distance after a certain threshold, so that a squad can have a fairly loose set-up (50 or more meter radius from their SL), but increase at a certain rate after that, so that you aren't as effective if you're not in the radius. Seems alright to me for simulating the pretty pants-filling feeling of being isolated from the squad in the jungle, heh. Also wouldn't be bad if the battlechatter system ingame was edited so the Sarge started shouting some classic 'return-fire-you-maggots' lines once the squad is being suppressed.
That would also provide the dilemma of whether the SL will lead the assault element so that they are more effective or have them assault on their own and guide the fire of the support element so that they are more focused, e.g.