Retweet from multiple accounts

I mange two related accounts for one brand. Sometimes both accounts are tagged in a tweet, or sometimes only one account is tagged but I want to retweet from both accounts. However, Sendible doesn't allow me to choose which accounts I want to retweet from. I can type in the handle of my other account, but the dropdown won't populate it. I previously used Hootsuite, which as a "Retweet from" option that allows you to select the account you want.