@Scaredgirl: Thanks for the art ^^
i think we may be speaking a different language sometimes lol
i am not suggesting that it split into several cards, rather have it be one card, one creature, one low attack value (1-2, this is a defensive card, like amigo), the ability be like amigo's where it is clicked to turn on, have the creature take damage each time the effect is triggered. renaming to something which depicts a single creature, rather than a multiple "convoy", would by my suggestion. not suggesting that you change the element, but it may work just as well as a / duo.
I would hate for Convoy | Convoy to be an inexpensive card. Again, I don't want it to be something you can just put 6 of in a 30-card deck. For this reason, a 1/3 as weak creature that does the same thing (sacrifice itself) for the same cost is too underpowered, and a weaker creature that does the same thing for 1/3 the cost wouldn't have the same effect, mechanic, nor theme as Convoy | Convoy. For this reason, I would most likely react to your suggestion by switching convoy to a creature-producing spell rather than a single creature.
I just don't see the connection to Gravity; the relation Convoy has is that it has >5 HP. If the creatures do not have low HP, then it wouldn't be the same because the individual members of a Convoy are not extremely sturdy, and I'd have to use a "sacrifice" mechanic rather than a "health decrease" mechanic. In addition, the act of moving together for mutual protection seems more Life than Gravity to me.