Sadly tables do not support exploding dice. If you get a 6 on your result, you'll need to make a new table roll.
What you could do is decide how many explosions to want, and then create a table with the full range of possibilities using the weighting entry.
For instance, if on a roll of 6, you get an extra d6 added to it, that would look like this:
Result | Weighting |
1 | 6 |
2 | 6 |
3 | 6 |
4 | 6 |
5 | 6 |
7 | 1 |
8 | 1 |
9 | 1 |
10 | 1 |
11 | 1 |
12 | 1 |
I know that's not how it works in your game; this example is just to illustrate the concept.