Virtual grouping balance

I want to put as much money in a S&S ISA to avoid the tax added on by using a GIA.
However, it is daunting having so much money in an account that I also want to use for small day trades.
The idea as an example:

ISA (name: “Stocks and Shares ISA”, balance: £6000, max: 20,000)
|
| split…
/
Group 001 (name: “Long-term”, balance: £5000, max: shared)
Group 002 (name: “Short-term”, balance: £1000, max: shared)

The splitting doesn’t have to be perfomed on any deep level, it can simply be programmatically forced and just have all investments go through the same investment account. It’s simply a visual thing, but it’s a lot nicer to look at imo.