It is expected that future wireless systems will consist of several distinct radio access technologies, forming a multiaccess system offering voice and multimedia services. Previous works have shown that the combined capacity region of such systems depends on the service allocation policy that assigns user sessions to the subsystems. Current policies typically operate off-line, implying that the service mix is known a priori. In this paper we consider the on-line problem where sessions arrive one after the other and no assumptions on the service mix can be made. We study the performance of four on-line bin-packing algorithms by simulation and show that the algorithm termed LessVoice provided the best performance in terms of blocking probabilities and throughput.