We discuss the problem of wormholes from the viewpoint of gluing together two
Reissner--Nordstr\"om-type universes while putting between them a segment of
the Nariai-type world (in both cases there are also present electromagnetic
fields as well as the cosmological constant). Such a toy wormhole represents an
example of one-way topological communication free from causal paradoxes, though
involving a travel to next spacetime sheet since one has to cross at least a
pair of horizons through which the spacetimes' junction occurs. We also
consider the use of thin shells in these constructions. Such a ``material'' for
wormholes we choose taking into account specific properties of the
Nariai--Bertotti--Robinson spacetimes.Comment: 5 pages, a talk delivered at the 11th Marcel Grossmann Meeting (2006