While doing multipitch climbing on rockfaces, the lead climber usually finds a small ledge or something like that to anchor themselves, and pause and top belay the other climber.
How does this process work on icewalls? Standing on the ice wall even after anchoring oneself to the tubular piton is hard enough, I don't think that is a pragmatic stance for belaying.
Or is multipitch not done on icewalls?
Perhaps the only way is to recce the route in advance and go with enough rope so that the lead climber can get to the top of the wall and then belay the other. Even that introduces complications with joining knots having to pass through carabiners but this is a somewhat solvable problem if one uses larger carabiners. Otherwise no pitch longer than a ropelength can be done.