Starting from seesaw-type linear macromonomer azide similar to similar to alkyne similar to similar to azide, where "similar to similar to" represents polystyrene with a controllable length, we successfully obtained two series of narrowly distributed "defect-free" hyperbranched polystyrenes with an identical subchain length but different overall molar masses or with a similar overall molar mass but different subchain lengths. Our ultrafiltration study reveals that the critical flow rate (q(c,b)) to pull these branched chains through a small cylindrical pore under an elongational flow field depends on both polymerization degrees of the entire chain and the subchain (N-t and N-b) as q(c,t) similar to (NtNb phi)-N-gamma, where gamma and phi are 1.0 and -0.4, different from those predicted values gamma = 1/3 and 1/4, and phi = 1/15 and -1/4 for the weak and strong confinements, respectively. Besides the previously improper assumption of each blob as a hard sphere, such discrepancies are also attributed to (1) a smaller scaling exponent between the size and molar mass of the chain squeezed inside the pore because it is not a chain free in solution and (2) for a given pore size, the hyperbranched chains with different subchain lengths are in different confinements, making the determination of phi less meaningful. In addition, q(c,b) is related to the pore size (D) as q(c,b) similar to D-0.8. Finally, we have demonstrated that the current quantitative study enables us, for the first time, to use small cylindrical pores to separate large hyperbranched chains by their structures (different subchain lengths) and topologies instead of their sizes.