Ntfy custom parameters?

[ShinySaana]

Say I have users a, b, and c.
They have their own private ntfy topic, a-notifs, b-notifs, and c-notifs.

I don't wish to repeat myself, and I only want one url in my config, ntfys://tk_token@ntfy/<something>-notifs, espcially since i may have user d tomorrow.

Is there any way I can template this <something>, somehow?
If not, is there a way to do ntfys://tk_token@ntfy/<something>, at least?

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My actual use case is not about users, but this example is enough.