renting land and deeds

If I rent land and it is deeded to a group, and then I allocate my 512m to that group, do I get the extra prims in my plot of land even tho there isn't actually any more land?

First it's worth pointing out that contributing tier to a group will not help you hold land on private estate sims, it's only for the maingrid. Second, that's all it is really, it will not increase your prim allowance at all. Allocating your tier to group is just a tool that allows more than one player to share the tier burden of a plot.

thanks.