Are there services that offer USSD number sharing among multiple clients?

Question

mobile connection

Now we are using 2way-SMS service from Infobip, but communication via USSD would be much more convenient for users in our project.
As it turned out, in order to connect USSD, you need to buy a short number (of the form * 142 # - from all mobile operators: Megafon, MTS, Beeline, TELE2) at prices from 25 to 90 thousand rubles for each. This does not include a fee for each message (about 1 ruble for MTS and Megafon). This is very expensive for us.
I thought that there must be a service that allows a large number of clients to use 1 number for USSD requests, but at a lower cost. The number in this case will be of the form, for example: *142#xx#... I could not find such a service. Are there such services? What prevents to implement such a business model, if not?

Answer 1

What hinders the implementation of such a business model

Probably prohibitions on the part of the operators)