A modular apparatus is configured to cause received rods of smokeable material to undergo a first sequence of operations. The modular apparatus can be reconfigured so as to cause received rods of smokeable material to undergo a second sequence of operations, different to the first sequence of operations. The first and second sequences of operations respectively form at least part of first and second processes for assembling smoking articles, each smoking article comprising one of said rods of smokeable material, which is smoked in use. The modular apparatus comprises a first inserter configured to insert a first rod article (33) between two tobacco rods (32a, 32b), a first rod divider configured to divide the first rod article into at least two parts (33a, 33b), a separator configured to separate a first group (34a) comprising a rod of smokeable material and one of said parts from a second group (34b) comprising a rod of smokeable material and another of said parts and a second inserter configured to insert a second rod article (35) between the first and second groups.