We have two groups, all following their own sub plot, a stage is reached in the story where both groups are going through a phase of repetitive actions (i.e. military training and long distance traveling) which the reader really doesn't want to hear about. So my question is, how do we progress by several years for both groups without jumping forward and backward through time to explain that time is moving forward with each group. I'm perhaps not explaining this brilliantly, so feel free to ask any questions. Brains a bit frazzled from staring at the page
I'd just pick the point in the future where the action picks up again and start writing there, writing scenes for each group as it comes up in the story. No explanation necessary. The reader will follow it.
I use a line of dots very simple hold shift and press 8 three times then hit enter releasing shift. That way I can still leave spaces knowing that people will see that as a jump forward for one character and not changing to another.
Just an idea but a birthday might be a good little device to use, say if in one paragraph "Ted" or whatever you call any of yoru characters is 21 and after an ellipsis or some other form of punctuation its their birthday again and they're now 28 or something along those lines.