Ah, I see where you're coming from.

If you join in on a club ride, generally they tell you from the outset the average speed and expected difficulty of the ride (most clubs post rides on their website and/or in the monthly newsletter, along with some kind of rating with regards to avg speed and amt of climbing).

Most clubs suggest that at the beginning you choose club rides that might (on paper) seem a little easy to you, in order to give yourself a chance to become familiar with the rating system and to lessen the possibility that you'll inadvertently join in on a ride that's over your ability at the time.

And most club ride listings include email or phone number for the ride leaders so you can ask them questions about the ride to see if it's within your ability.

On the other hand, if you're going on an impromptu ride with a bunch of friends, then hopefully they'll understand that you're a beginner and they won't try to hammer you into the ground

So all in all, I don't think it's the same sort of situation as you had with the mtn climbing.

Plus, seems to me you already have the sense not to be 'that guy' on a bike