Similar situation flying to the US in September.
There was 6 of us - 1 x SG and 1 x QP member. At first they said no, we could only have one guest each...but eventually they gave in.

(SYD T3 QP)
I'd say if you only wanted one additional guest, it'd take a pretty strict QP staffer to say no. You could always guest one in, then guest the other 5 minutes later.
Results may (and most probably will) vary.

I'd imagine having QF WP would help too.
Cheers,
- Febs.