The MediaCityUK firm will also launch a new brand for the Nexbridge later this year.
WHYPAY? is a free conference call platform that uses a dial-in number included in bundled minutes whether calling from a fixed or mobile telephone.
The Wonderful Organisation has been set up by Nexbridge chairman Kieron James as a not-for-profit fundraising platform.
“We’ve appointed Rule5 because they understood our businesses and have a strong track record of delivering effective PR campaigns,” James said.
“We have some major announcements in the next six months including a new focus for Wonderful.org and a new brand that will have a major impact on the conference call sector.
Rule5 managing partner Rob Brown added: “Lots of people talk about disruption but Nexbridge has plans that will have a real impact on the corporate conference call market and the charitable giving sector.
“We are really looking forward to launching several genuinely innovative products and services.”