I guess you mean GC who also happen to be related to the Outcasts. I know who might that be.
In any case, they shouldn't have been attacking your Order, unless you were in their guard system or something. I am sure you weren't.
Guys, you need to stop thinking like this, "this guy is a noob so I can kill it without thinking much, he won't care anyways or nobody would believe him."
Just do what your ID tells you to do. If your character hates something and feels friendly to something, that doesn't mean your ID and the faction RP that clearly defines what you are allows such acts.
If you even manage to make it sense, expect trouble the very same way from your allies, the blood dragons themselves, hunting for your head. I might just do it.
Send an in RP PM to the Blood Dragons NoMe. Post proofs and such things please.
Simply speaking, NoMe. If your IMG got pirated or killed, you don't bring an Order Osiris to ... yes, Tau-23, and try to kill people for shooting IMG. Do you know how is it called? Also, check what you ID allows. If you call GC (not even our \W/, we actually don't shoot IMG in most cases, so you even found not the GC group you were looking for) infected because they attack IMG, perhaps you should change your job. If you stumble upon people RPing with nomads, perhaps you could pay attention to what is really happening instead of ... actually being uanble to link a couple of words in RP. And when you don't have respect to GC in general, don't be surprised to get destroyed. Especially in a system you shouldn't be in principle