Yes, you can split one cell into two cells in Excel without affecting the filter/sort functions. Here's how you can do it:

1. Select the cell that you want to split into two cells.
2. Click on the "Home" tab in the ribbon.
3. Click on the "Wrap Text" button in the "Alignment" group. This will allow the text to wrap within the cell.
4. Place the cursor where you want to split the text.
5. Press "Alt + Enter" on your keyboard. This will insert a line break and split the text into two lines within the same cell.

Now you have two lines of text within the same cell. You can use the filter/sort functions as usual without any issues. If you want to split the cell into two separate cells, you can use the "Text to Columns" feature. Here's how:

1. Select the cell(s) that you want to split into two cells.
2. Click on the "Data" tab in the ribbon.
3. Click on the "Text to Columns" button in the "Data Tools" group. This will open the "Convert Text to Columns Wizard".
4. In the first step of the wizard, select "Delimited" and click "Next".
5. In the second step, select the delimiter that you want to use to split the text (e.g. space, comma, semicolon, etc.) and click "Next".
6. In the third step, you can choose the data format for each column. You can leave it as "General" or choose a specific format if needed. Click "Finish" when you're done.

Now the cell(s) have been split into two separate cells, and you can use the filter/sort functions as usual.