Grouping Multiple Measure of Rests

What about this is unclear?

1. Ensure that the option to display multimeasure rests in the score is off (see above).
2. Right-click on the measure where you want the second multimeasure rest to start;
3. From the menu, choose Measure Properties and tick "Break multimeasure rest."

You need to to this on every 7th measure

Again: you need to interrupt the mmrests, just as described in the handbook

Here it is with the 1st and 2nd 7-mmrest
You'd need to geit into the measure properties and set the 'break multimeasure rest' box on those measures you want a new mmrest to start
Exactly has the handbook describes

As mentioned, in any published music, such a break would be accompanied by a double bar, or a rehearsal mark, so some other obvious reason for the break. And as I explained, as soon as you add that, the break happens automatically. You shouldn't need to mess with measure properties - that would be a sign that you left something out of your score that would have done this automatically.

So in the score (not the part), simply add a double bar at measure 55. Then when you generate the parts or enable multimeasure rests on the score (extremely uncommon in published music, musicians would not want to read this from the score rather than the parts) all will be as you expect.

So, the steps to follow are:

1) go to the measure 55
2) add the double bar, also probably add system text saying "guitar solo"
3) while you're at it, best to change the "bass solo" text at 47 from staff text to system text, because you'll want that to show on all parts, not just the voice part where it is currently attached
4) File / Parts to generate parts

When you do that, you'll see each parts rests break right where they should. Or, if for some unusual special reason you are asking people to play from the score rather than their own individual parts and hence you wish to enable mmrests on the score itself, press "M" instead of using Fie / Parts, and again, all is perfect. but that doesn't really make sense, if it's an mmrest, how would the guitar playing reading the score know what to actually play during that solo?

But, you also have a more fundamental problem with your score, you have tenor saxophone parts but the transposition is not set up properly. Did you do something unusual hen you created this score? Something other than simply selecting instruments from the dialog that appears when you do File / New to create a new score? As it is, you're going to have chaos I'm afraid as the saxophone parts will be in the wrong key.