I think if they are part of a private group they can. Good question though
I hope other commanders can help in open play
I am in the same boat as the OP, took a mission (mine ends at 11:00am tomorrow), need to complete it tonight. Had a go last night, Fed Dropship for me. I am in an Adder, so my top line speed seemed better, guns and defence not so much :lol. I was holding my own mind, 69% hull for me, had the dropship down to 79% - slow goign but figured my tactics and power out so was prepared to grind it down. The cops showed up "to help" and shot one accidentally, so advanced in another direction in Supercruise.
Upped my guns (need to be careful I have fixed MCG) - got a shield bank (or 2) time to have another go tonight. Bring it on, but if anyone is around I will beg for help for some cargo, but I am a bit skint at the moment....
Simon