You're not allowed to parallel.
You can't parallel through relays because you can't parallel generally.
In US NEC, it is disallowed except for currents so large that single wires are not readily available. I don't have a cite but I'm sure the EU model codes have the same rule, since it's a basic physics problem.
And even then, each paralleled conductor must be fused separately. (For instance I have an 800A 3-phase service with conductors paralleled, each on a 400A fuse. The conductors are 1000kcmil, the next size up is hard to procure.)
They must be the same material and length and terminated in the same manner, so they have the same electrical characteristics - that's to keep current from favoring one path over another. (which would result in a cascade of fuse blows).
This "favored route" problem will be even worse if you have contacts making (or breaking!!!) not quite simultaneously.
And remember, those small electronics relays aren't necessarily listed for use switching mains voltage. Their ratings as a component only mean they can be used as a component in an assembly/product/machine, which must then go back to the testing lab to be listed as an assembled machine.
Just use a big contactor. If your controller don't have the oomph to throw the big contactor, use a little relay to throw the contactor's coil current. This does an end-run around the snubbing problem; you only need to snub the little relay (though it will reduce arcing on the little relay's contacts if you snub the contactor's coil).
Or if one contactor is too expensive, you may be able to use several.
Multiple contactors are ok on multiple loads
I am inferring that you have more than one load. It's not paralleling to use one contactor per circuit or load. If each of your loads is <=30 amps, this is easy and cheap.
Suppose you have a 30A compressor, you can control that with a 30A contactor. As it happens, the HVAC industry has plenty of Code-rated 2-pole 30A contactors with 24VAC coils in the $12 range. 24V transformers are also in the $15 range. Here's a combo. Note how some of them are designed to mount in the cover or a knockout of a standard junction box.
If you have several loads on one breaker, you can just use another similar contactor on another circuit. If the contactor is 2- or 3-pole, you can switch one circuit per pole - that's not paralleling.