All of my Chi's play together. Milo is the least likely to play (he's my lazy Chi) but the others at times do get him riled up & he joins in on occasion. They do have their favorite playmate though. Like Mari & Marley play constantly & Matilda & Maxie are most likely to play. Marley will play with everyone though...he's our busy body. LOL Come to think of it...Mari & Matilda I don't often see playing with one another. It's usually the boys with one of the girls. Matilda was our first & was great accepting all our boys (Marley she took on as her own at first & was very protective of him) - but with Mari...it took Matilda a while to adjust. I do half blame my hubby because he has always favored Matilda which makes it hard. Anyway, as long as you always treat pups equally and YOU are their pack leader there should never be a problem.
Just a warning though - if you do decide to get another introduce gradually & don't expect them to hit it off at first. Milo attacked Matilda constantly when we introduced them at first (even though he was the newbie) - I was ready to give him back to the breeder but agreed to give a couple weeks & in a few days they were best of friends. It can take a while for them to adjust but in time...they will! Just wanted to share a bit of that story so you don't have any surprises like I did. I was devistated when we brought Milo home....
None of my pups get jealous of one another if they're sitting with me & another come near - but to achieve that again YOU have to be the pack leader. I often have all my pups sitting in my lap & if anyone growls they get reprimanded & have to leave the "pile".
But we generally don't have an issue.
They each have their favorite toy but typically everyone wants the toy (or bone) someone is already playing with if you kwim. Just like children. LOL Matilda is also our bossy one when it come to toys or fetch. Not in a mean way...she just will take what she wants when she wants it. If I try to play fetch with someone other than her, no way. She beats them to the catch every time. So if I want to play with someone else...I have to crate her or hold her back.
Also, it is important for pack activity & attention - but it is also important they each get their own 1 on 1. I make sure to take time each day to pet & talk to each of them seperately w/o allowing others to come steal the attention. As easy as this sound - it can be quite difficult because you have those who beg for attention all the time (Marley & Matilda) - then you have those who never really "ask" for loves (like Milo). So I just have to keep an eye out & make sure Milo gets some loving too as well as the others.
I know many people say to treat your first "special"...give them treats first, pets first, etc. I find this a total NO NO! That only encourages your first to become alpha (which is YOUR job). Treating equally is the way to go to avoid any dominant behavoirs. Being bossy is one thing - being dominant is another.
Anyway, good luck with your decision!