I can think of three possible solutions to your problem:
You could request the amount for the people who owe you using the Request feature in the Payments tab. Although, you’d need the ability to track these pending requests, which currently isn’t possible. The ability to manually send request reminders could also be useful.
You can vote for the ability to track pending requests here:
You can vote for the ability to manually send request reminders here:
The ability to add notes to pots could also help since you’d be able to create a pot, set the goal as the total amount you’re owed and then put a breakdown of what you’re owed and why as a note on the pot.
A Shared Tab could be used to do what you’ve suggested:
Create a Shared Tab with the person(s) who owe you money.
Add a manual transaction for the amount they owe you.
When they pay you back you can get them to add the amount they’ve paid you as another manual transaction.
Although the ability to partially settle a Shared Tab would help them easily pay you back when they can.
You can vote for the ability to partially settle a Shared Tab here:
Since you’d like to see a full transaction history between you and the people who are paying you back, I think option 3 if the best idea (as @StuartMac suggested).
If it’s a small amount and you think the other person would be able to pay you back in one go, then personally I think option 1 (with the ability to track requests in the Payments tab) is the best option.