"Lord, if it's not your will, let it slip through my grasp and give me the peace not to worry about it anymore." - however, if something is going to slip through your grasp it may require actively opening your hands
OP said: 'Sometimes I feel like I have part ownership of say, the Bennet family.) Oh, and An Old-fashioned Girl- completely. Polly Milton and Tom and Fanny Shaw are old, old friends!' I completely agree.