Supposedly One for All originated as 2 quirks, one quirk to stockpile power and another quirk to transfer itself. Then both quirks merged (supposedly) , and after that every quirk from every user of One for All was added to the stock of transferable quirks that was passed everytime One for All was transfered. So now Midoriya has 7 quirks (or 8, depending if you count the original One for All as one or two), and he's able to use 4 or 5 (again, depending on how you count them). So, could Midoriya take one of his quirks like Blackwhip for example, and transfer just that one? Or can he just transfer all the stock of quirks altogether?
Not sure what you are asking. The "quirk transfer" was part of One for All and it transfers everything that has been accumulated in One for All. Also, the so-called "stockpile energy" comes from all the previous owners strength and quirks merging together within One for All thus granting the users a surge of power. They aren't 2 different quirks.
One For All is a transferable Quirk that can be passed on from one user to the next. One For All also allows the user to stockpile an enormous amount of raw power, allowing them to significantly enhance all of their physical abilities to a superhuman level. This results in unbelievable levels of strength, speed, agility, and durability.
Up until now, there isn't a record of other owners of One for All that could use previous quirks and Midoria is the first one to do it ... so we still don't know the full extent of this new side of One for All.
But to answer your question: No, Midoria can't only transfer one quirk or part of One for All since those are embeded in the core of the quirk and it comes as a whole package.