Spread spectrum packet-switching radio devices (22) are operated in two or more ad-hoc networks or pico-networks (19, 20, 21) that share frequency-hopping channel and time slots that may collide. The frequency hopping sequences (54) of two or more masters (25) are exchanged using identity codes, permitting the devices to anticipate collision time slots (52). Priorities are assigned to the simultaneously operating piconets (19, 20, 21) during collision slots (52), e.g., as a function of their message queue size or latency, or other factors. Lower priority devices may abstain from transmitting during predicted collision slots (52), and/or a higher priority device may employ enhanced transmission resources during those slots, such as higher error correction levels, or various combinations of abstinence and error correction may be applied. Collisions are avoided or the higher priority piconet (19, 20, 21) is made likely to prevail in a collision.