Mona from Sheffield asked us not long ago, how to go from alicante airport to benidorm in a taxi being that there was 6 of them. The taxis that I have seen at the airports of Alicante and Murcia are the ones which can take four passengers comfortably with their corresponding luggage. There are usually taxis waiting and I think it would be better to just get two taxis. It would probably be quicker and easier.
But if you feel better traveling altogether than you could have a look at a detailed list on some alicante taxi companies by just going here:
https://www.alicante-spain.com/alicante_taxi.html
If you are staying at a hotel, there is the possibility that they will offer you this service. Check it out!