edit cell names all at once?

[pzaz]

Hello -
I have a large spreadsheet with many custom cell names. these cel
names are referenced by formulas in other sheets.

I need to duplicate this sheet for the next trimester and I want t
change the names accordingly.

for example:
the "T1" in these five cell names
mkRS5T1L5
mkRS5T1L4
mkRS5T1L3
mkRS5T1L2
mkRS5T1L1

will change to "T2" for the second trimester, like so:
mkRS5T2L5
mkRS5T2L4
mkRS5T2L3
mkRS5T2L2
mkRS5T2L1

But I don't want to have to change each cell name one at a time - ther
are close to a thousand of 'em.

Is there a way to edit the cell names in bulk, so to speak?

Thanks in advance-
Pzaz

for those who are curious, the rest of the code in the cell names goe
like this - the first two letters are the school name, next is th
assessment and grade - RS5 = Reading Strategies, 5th Grade, then whic
trimester. the last bit is the level - L4 = level four or