Joint birtday party - present presumption?

[Bombay2Goa]

My lo is going to have her b'day party with two of her nursery mates. They are all turning 4 and this is the first party being thrown for them (and the last one before they all go off their separate ways to school this year). The invites will be going out to all their common mates attending the same nursery. LO's mates mums think we should put something on the invite to say 'bring only one present' (as the invitees will know all three girls). I was hoping we would say 'no presents'.I understand its a kids party and the birthday girls are turning 4, and I think they know they will be getting presents. How do I best put in words on the invite to bring only one present with out sound presumptuous and rude?
Ive read some of the other threads here on joint birthdays and gift-giving , and now I'm a bit worried on how to put this 'clause' on the invite in the politest way possible..
Yes, I got the task of writing the invitations...

So, all of the children are fiends with all of the hosts? Each would invite all the other children (including the other 2 hosts) if they were having separate parties?

TBH I think you need to either do a flat No Presents edict or each child needs to send their own invitation.

Joint parties are difficult. I've never done one with more than a 60% ish crossover in invitees, individual invitations from the host worked well there. They each invited the other too.

Could you just say that if they wish to bring a present then one present is fine as At the end of the party all presents will be divided between the girls.

Thankyou notMarlene and Chocolatecake12. This is my first kid's birthday party and I've come to understand its not any easier when you have to get consensus from two other mums. Both are lovely - but I miss having my autonomy!