I ran this query on propokertools.com/pql
select count(minOutsToHandType(You, flop, straight, 8) or minOutsToHandType(You, flop, flush, 9)) as Enough_Outs
from game="holdem", You="56s", MP="QQ-AA", CO="22-AA, AQ"
Results:
Trials ENOUGH_OUTS
600000 107102 (17.85%)
That should be how often you'd expect to flop a "good" straight or flush draw multiway with 65s against QQ+ and 22+, AQ.
If you only care about outs for straights:
select count(minOutsToHandType(You, flop, straight, 8)) as Enough_Outs
from game="holdem", You="56s", MP="QQ-AA", CO="22-AA, AQ"
Results:
Trials ENOUGH_OUTS
600000 54054 (9.01%)
Also ran:
select count(equity(You, turn) > 0.5) as You_Ahead, count(equity(MP, turn) > 0.5) as MP_Ahead, count(equity(CO, turn) > 0.5) as CO_Ahead
from game="holdem", You="56s", MP="QQ-AA", CO="22-AA, AQ"
Results:
Trials YOU_AHEAD MP_AHEAD CO_AHEAD
600000 76600 (12.77%) 406348 (67.72%) 108872 (18.15%)
This should tell you how often each of you is ahead on the turn. (It's not clear what you meant by "ahead" on the turn, so I used > 50% equity.)
If you want the % you'll have at least a straight by the turn:
select count(minHandType(You, turn, straight)) as Straight
from game="holdem", You="56s", MP="QQ-AA", CO="22-AA, AQ"
Results:
Trials STRAIGHT
600000 49953 (8.33%)
And while I'm here, this is to see how often you lose (assuming both opponents stay in) when you have at least a straight on the turn:
select count(not WinsHi(You)) as You_Lose_Despite_Straight
from game="holdem", You="56s", MP="QQ-AA", CO="22-AA, AQ"
where minHandType(You, turn, straight)
Results:
Trials YOU_LOSE_DESPITE_STRAIGHT
171940 32661 (19.0%)
Anyway, as pointed out by earlier posters, the answer to whether you should fold or call in such situations depends on effective stack sizes and implied odds (in particular, how likely are these guys going to stack off with pair, two pair, trips against you on wet boards).