I think I have found an answer: rstudioapi:terminal* commands! Something like:
termId1 = rstudioapi::terminalCreate(caption="Server1", show = TRUE)
rstudioapi::terminalSend(termId1, "hostname; \n")
termId2 = rstudioapi::terminalCreate(caption="Server2", show = TRUE)
rstudioapi::terminalSend(termId2, "ssh uid@server; hostname; \n")