"Yes, can't have them combining forces against us."
Having weathered the group efforts of all three of his closest friends, Regulus really didn't fear the dual concerted efforts of Severus and Eames. They never harmed each other, no matter what Regulus claimed polyester did to his 'tender sensibilities'. And truth be told, he would be disappointed if no alliance was formed, if such an opportunity present itself.
"I'm sure Severus will be delighted at the amount of joy and cheer he brings to every room now."