Right now, Special:MergeItems and Special:MergeLexemes only allows to merge to entities.

Sometimes, especially for Lexemes, we need to merge more than two entities.

It can be done in multiple steps, merge two then merge the result with the third one. But if it's done in the wrong order (not the two bigger id with the smallest id), it results in a broken double redirect (and you need to unmerge and remerge). It can be messy and seems unnecessary complicated. Being able to do the merge all at once would be easier.