From my understanding your question is how to import both legacy segwit address (address starting with 1) and nested segwit address (address starting with 3) and then send the funds to two other addresses.

Create a new wallet in Electrum.

Select "Import addresses or private keys"

Enter private keys of both of your addresses.
Just note that you must add p2wpkh-p2sh: before private key of your segwit address.



Then you will have both of your addresses in a single wallet.
In order to be able to send bitcoin to multiple addresses, select "tools" at top of the window then click on "Pay to many".