This paper focuses on multiple sluicing (MS) utterances in which the antecedent for sluicing is syntactically complex, insofar as it contains at least one embedded clause. Complex antecedent MS (henceforth caMS) is subject to the clausemate condition (CC). Phrased in sententialist terms, the CC bans sluiced wh-phrases from being base-generated in different finite clauses in the elliptic clause. Under specific conditions, it seems that the CC is obviated. We report results from acceptability judgment experiments on German and Spanish that provide further evidence that elliptic wh-clauses in caMS can be monoclausal in nature and that these monoclausal elliptic clauses (so-called short sources) are judged as significantly more acceptable than their isomorphic, biclausal elliptic clause counterparts. We interpret these results as supporting the view that purported obviations to CC are only apparent, following Cortés Rodríguez (2022a) and Cortés Rodríguez & Griffiths (to appear). Because these experiments are novel in that they focus on caMS configurations involving syntactic islands, their results provide new insights into how putative CC-obviation and islandhood interact and demonstrate that not only personal but also relative pronouns can function as correlates in MS.