so yea an or item or hullmod or ability that makes enemy fleets think youre an ally when you turn the transponder off (if you dont get too close)
perhaps the item route could involve putting whichever one you want active at the end of inventory
a skill gained from the sensor tree (or hullmod)
or maybe a set of hullmods wherein you oufit enough ships with a factions version to trick them into thinking youre allied unless you get specifically scanned by a patrol
or maybe a one size fits all version of that
personally i like the idea of it being item based, and you would have to collect them, perhaps from underworld types in bar events, or whatever other way seems appropriate and fun