If they belong to the same gym or something similar, then I can see that being useful. But just grouping them for the sake of grouping them is not correct.
That's like creating relation of every single sidewalk in NYC...

Please don't misunderstand. I'm not saying those features shouldn't be mapped. By all means, map them and add details with correct tags.
However, in this case I don't see a relation being appropriate just to group them togather.