I will just give a few examples as I think that is the best way to describe what I want, but basically I want to only keep the number but prepend text to the start depending on the first number (1 or 2: AAA, 3: BBB, 4 or 5: XYZ):

INITIAL STRINGS:

```
Blah 12345 Blah
Blah 22345 Blah
Blah 32345 Blah
Blah 42345 Blah
Blah 52345 Blah

```

RESULT:

```
AAA12345
AAA22345
BBB32345
XYZ42345
XYZ52345

```

Regex to search for:

```
([0=9])([0-9]{4})

```

Regex To replace with:

```
(SOME WAY OF DECIDING BETWEEN AAA|BBB|XYZ depending on \1!)\1\2

```

Is this possible?