Forward calls to messenger Is it possible to forward network calls on an Android mobile phone through a messenger, like Telegram or Whatsapp, to a set contact? 

Could IFTTT be used for this?
Call forwarding is a telephony or carrier function. It works amongst voice networks or some VOIP sites. For it to work with messenger apps:


They should mutually allow it, which is unlikely given the revenue models of voice calling (at times call forwarding is a paid service even for voice networks) .
Security concerns - for example, if the calling number cannot be identified across messaging apps, it would not be permitted. There could be more such scenarios.
Encryption. Voice calls of WhatsApp are encrypted. Same is the case with
Telegram.
They would not like to expose or let others use their proprietary encryption. 


There may be more reasons too. Only after it is legally and financially viable a messaging app will expose an API that can be used for this. Till such time this is possible, automation is ruled out irrespective of the app