can i make an ultrasonic sensor send and receive certain frequencies?

we want to use two sensors for different functions and we fear their signals might interfere with one another so we had an idea of manipulating the frequency of one of them but we don't know if it'll work or not.. if you don't think the signals will interfere with each other or if this is possible or any other way please help, thanks.

No, you can't. But you don't need to. There is no interference as you will send/receive from only one at a time and alternate.
Also stop making new threads for your project questions.