Right now the way to specify the resolver and contracts for a specific TLD is
--ens-api test:<contract 1>@<address 1>
--ens-api test:<contract 2>@<address 1>
The rns resolver uses a similar approach but for only one TLD (.rsk)
--rns-api <contract 2>@<address 1>
This was introduced in #1939 as a workaround.

The correct way would be to unify both under a common flag for example
--resolver-api=ens:<contract 2>@<address 1>
--resolver-api=rns:<contract 2>@<address 1>