At a previous unit we were able to get in touch with three local Squadrons who were all radio savvy (as in had a clued up Radio Officer on unit)
All needed VHF to make it worthwhile and all were 6-10 miles away. Any further and we never made contact.
It helped that 2/3 shared the same parade nights offering flexibility, while the other matched one parade night so was a bit harder to coordinate as we could only consider 50% of the parade evenings and only then if it was convenient for both units.
so if you mean by “working with other Squadrons” = via radio
consider if anyone is in range of your kit,
then consider if they have the kit available,
then someone who is comfortable using it.
Although HF is the obvious choice for distance this is not the easiest for use during Parade evenings - mornings tend to work best (as I understand) and requires effort to firstly find someone and then coordinate with Squadrons outside of your Wing or even Region.
Far easier to consider VHF and a ~10mile range.
then just a matter of designing an exercise. the trick with Radio exercises is make the exercise easy so the effort and thought is in the accuracy of radio procedures and use and not the exercise itself.
as an example we’ve played “Guess who” over the radio, a familiar enough board game means there is no learning of the exercise involved.
Alternatively take a look at ACP 044 Chapter 9 (Sharepoint link) which has other Radio exercise ideas
if you mean by “working with other Squadrons” = joined up training, I am sure any Squadron would be happy to discuss options. Your Wing Radio Officer may well be worth chatting to on this topic to coordinate a Blues course as part of the effort