could you add a ctf flag? it would work jsut like a flag in ctf gamemodes but every team can pick it up and carry it (even its own team to get it back int its place), you could make it to be assigned just like the spawn,the flag is static and cant be moven or tipped over without picking it up, when you put it down its no colide for a while and it drops right at your feet, also when carrying it it woul slightly slow you down, you can ride with vehicles in it, you can't pick it up with gravity or phys gun, last thing it would send a messagewhen a team picks it up (also the name of the player and the message would be in the color of the team that picked it up)
thats it i hope that you can do that, sorry for my english i tried to make it as clear as i could. have a nice day ;)