I hike alone, but am aware of the
Association Vaudoise de Tourisme Pédestre (site only in French!). They organize many
group hikes.
A quick search showed that EPFL has a
Club Montagne EPFL; much of their web site seems to be "under construction" but the club seems real enough!
In my haste to search for the relevant associations I forgot to start with a

to the EF and to Switzerland