Hopefully two relays in parallel will work, but if the load exceeds to ability of one of them, the chances are that the two will not be synchronised to the nearest microsecond, and one will always "win", and briefly carry the full start-up load. This will shorten its life expectancy. "The first one now will later be last" - Bob Dylan.
Lots of parameters around relays. There is switching current and carrying current. The switching figure is usually a good deal lower than the carrying current, since the pressure between the contacts is at its lowest at that point. Or points. You look at a scope monitoring a relay contact in enough detail and you find that the trace looks like a round of applause. Then tere is the contact voltage - this becomes important on release, where inductive loads' back emfs try to strike an arc during separation.
Simplest way is to have a modest size relay work one with heavier contacts.