As Mr. Cool said, it can be done. Usually, after servicing an interrupt you run a retfie command that sets back the GIE bit. No one can stop you from re-enabling the interrupt before fully servicing the previous interrupt, so can be re-interrupted.
BUT, it is very risky and several things should be considered. It is very important to first acknowledge the interrupt and then set the GIE bit. Because if you don't clear the xxxIF bit, re-setting the GIE will keep firing again and again the same interrupt endlessly and poof, you're stuck...
Next have in mind that the same code at the beginning of the interrupt will be re-executed. For example, usually you save W and STATUS when entering the int and restore it on exit. If using a static save method e.g. a single memory position for each register, if you re-interrupt you will loose the initial W and STATUS values.
And of course there is always the 8-level deep stack
I guess that it would be best to use polling inside the interrupt, but only you can decide that.
Regards
toxadi