  A critical ingredient for realizing large-scale quantum information
processors will be the ability to make economical use of qubit control
hardware. We demonstrate an extensible strategy for reusing control hardware on
same-frequency transmon qubits in a circuit QED chip with
surface-code-compatible connectivity. A vector switch matrix enables selective
broadcasting of input pulses to multiple transmons with individual tailoring of
pulse quadratures for each, as required to minimize the effects of leakage on
weakly anharmonic qubits. Using randomized benchmarking, we compare multiple
broadcasting strategies that each pass the surface-code error threshold for
single-qubit gates. In particular, we introduce a selective-broadcasting
control strategy using five pulse primitives, which allows independent,
simultaneous Clifford gates on arbitrary numbers of qubits.
