Binding const references to const values only

I am working on a code that finds pairs (using a specific condition) among the elements of a collection. I don't really want to duplicate the elements of the collection, so I figured I would use pointer pairs. This however is unsafe if the values in the original collection can change.

In my code I would like to use a const reference that only binds to truly constant values (because I don't want to let the users to abuse the pairs). This approach however:

using PairCollectionType =
    std::vector<std::pair<std::shared_ptr<Cluster>, std::shared_ptr<Cluster>>>;

PairCollectionType getClusterPairCollection(
    const std::vector<Cluster> const& clusterCollection)
{
    // ...
}

-> results an error of "duplicate 'const'". I know that this is possible with pointers:

const ptr_type* const ptrThatBindsOnlyToConsts;

Is this somehow possible with references too?