That riding would stay as a single-seat riding. It could be a Switzerland in the middle of a multi-member riding around it. I don't see any particular problems with that.
The complication is each riding has to know what's on the table. There does have to be some coordination. If riding A wants to merge with riding B, and riding B is more interested in merging with riding C, there does need to be some coordination there. However, as I said, in most parts of Canada there are obvious urban blocks or geographic delineations that would lead to obvious grouping, and that's what the petition process would have to figure out.