We study the effect of hindered aggregation on the island formation processes for a one-dimensional model of epitaxial growth with arbitrary nucleus size $i$. In the proposed model, the attachment of monomers to islands is hindered by an aggregation barrier, ${\ensuremath{\epsilon}}_{a}$, which decreases the hopping rate of monomers to the islands. As ${\ensuremath{\epsilon}}_{a}$ increases, the system exhibits a crossover between two different regimes; namely, from diffusion-limited aggregation to attachment-limited aggregation. The island size distribution, $P(s)$, is calculated for different values of ${\ensuremath{\epsilon}}_{a}$ by a self-consistent approach involving the nucleation and aggregation capture kernels. The results given by the analytical model are compared with those from kinetic Monte Carlo simulations, finding a close agreement between both sets of data for all considered values of $i$ and ${\ensuremath{\epsilon}}_{a}$. As the aggregation barrier increases, the spatial effect of fluctuations on the density of monomers can be neglected and $P(s)$ smoothly approximates to the limit distribution $P(s)={\ensuremath{\delta}}_{s,i+1}$. In the crossover regime the system features a complex and rich behavior, which can be explained in terms of the characteristic timescales of different microscopic processes.