Groups are inherently closed, have a high-barrier to entry, need constant attention to keep up. They are formed usually due to the proximity of people, common characteristics or even due to similar problems.
Networks, on the other hand, are open, have low or no barrier to entry, are extremely diverse from deans to doctors, CXO’s to compounders all form a network. And one can easily co-mingle among them.
Building networks is a better investment of time, energy, money and sanity if you are just starting out, in college or building something that matters.