I will try to explain this as succinctly as possible, but I'm not sure that I'm great at that so please bear with me...

I download a lot of custom content from one particular creator who makes a lot of really cool and unique items, often items that groups of Sims can interact with together. For example, a bouncy castle. (That is not an actual thing, but wouldn't that be cool!) If the bouncy castle is on the lot then you can click on it and get a "Bounce with..." command that then lets you pick the Sim that you want to go bounce with. These items are all really amazing and the animations that go along with them are incredible, my problem is that the interactions for the items also appear when you click on an individual Sim as well, and they appear even if the item isn't on the current lot. And they tend to be the first interactions listed when you click on a Sim. And when Sims are left to chat on their own they tend to choose these interactions a lot. So when I'm playing a Sim I have to click through a lot of these interaction options to get to "Discuss Interests" or "Cloudgaze" or whatever and when Sims are on their own there's a lot of asking another Sim to do something and then waving hands in the air and shrugging when there's no bouncy castle in sight.

Bearing in mind that my modding skills are caveman level at best, is there a simple way to remove these interactions from Sims while leaving them attached to the object?

Thanks!

(And also, could someone make a bouncy castle?)

You're being very vague.... it's kinda sus lol Why can't you tell who this is creator is?
If the object was made correctly, the interactions of the object should already only be tied to that object, unless you're talking about something much bigger, like some mod that affects everything with a ton of... animations...
Unfortunately, I'm not a modder, nor do I know how this mod was made...