hmm... the first thing to train your mindset is "never try to keep up or go faster to feel you belong in the group ride." that usually spell out disaster, imho and in my experience (not me crashing from keeping up, but others in our group).
i hear proficient motorcycling is good. some of keith codes books are ok. there's really no science to it. but making the bike dive into the turn isn't one good way unless you're trying to trail brake your way (which really shouldn't be done in the street also). i would start with just do all your braking while vertical, turn the bike, and slowly gas your way out. gas here means no wheelies. take is slow, but a sure way of getting into twistie riding.
not holding a line could result in different things. were you on/off the throttle? were you too hot coming in? was your body shifting all the time. hence my recomendation above of finish all breaking, turn the bike in, and slowly get on the gas. no shifting of body movement from hanging off is necessary.
letting off the gas is what most people will say is a big no no. but this depends on how fast you're getting and how loaded are the forks. in the track, the suspension is compressed and if you let go of the gas, the weight transfer will go forward thus putting more force down on the forks. if you reach the limit, the tires could give out. but again this depends on how hot are we talking about here. it's natural reaction to "coast" your way thru the turn if you're hot. i would keep neutral throttle to prevent shifting the weight from the back to the front. hence again, taking it slow by sure. (not preaching here, but really making a point most riders make a mistake on).
most people won't crash due to the rear tire. i think it'll be the front becuase people come in too hot, apply brakes too much then flick it in and let the dice roll (as they say). that's the problem of trying keep up. you'll gas it hard on the straight to get caught up... be very hard on the brakes.. turn... and then say the prayers.
it's weird how you brought this up. yesterday in my ride with my friend, i kept the straights sane and just carried the momentum into the turn (for those large sweepers). never really even passed 45deg lean or even close to it. but it's a great way to learn how to enter turns w/o the complexities of braking, trail braking, etc. someone taught me this in my newbie years and it really sank, not to mention reinforced by level 1 class with keith code superbike school (day 1, no brakes, light brakes at end of day, no shifting). it's a really good drill to ease you way into twistie riding, plus avoid the ticket for warp speed on the straights which is where most people get busted.
keep the questions coming. by asking, you've taken the first step already into the right direction. your friends should reinforce the "take your time, we're not going anywhere or leaving you."
now if you're local, i'll trade you buddy riding time with how to wheelie. i still can't even pull a power wheelie off a regeared gsxr 750. was too chicken to try it on the 1098S yesterday
"Leaders are like tea; put them in hot water to find out how strong they are." Anonymous