How do I put users into 2 different groups?

I need to have 2 different groups (g1 & g2). Please tell me how to step by step, setup the registration page to allow users to choose which group (g1 or g2) they want to be a part of. I then need to then have the users directed to their respective separate pages
(that will have different layouts, modules, components, etc... I have created two new user groups, but I don't know how to make it an option to choose from the users to choose from when they sign up (and I don't know how to do the rest of my question as well).

When you say groups do you mean Joomla ACL groups?

Yes, I believe so. I need to have either group also log into Kunena and Group Jive with the same credentials all with the one login; again, how?

jabrister wrote: Yes, I believe so. I need to have either group also log into Kunena and Group Jive with the same credentials all with the one login; again, how?

www.joomlapolis.com/support/tutorials/107-use-cases/18237-assigning-usergroup-based-on-cb-field-value

So, I went through the tutorial earlier in this thread, and as I've said, I have created 2 user groups. On the registration page there is an empty drop down with no choices, that says Profile type:.

How do I provide the choice for the users to choose which group they want to be part of on the registration page? I also now have the following warnings on the registration page (why/how can I fix the issue?):

Warning: reset() expects parameter 1 to be array, null given in /nfs/c01/h13/mnt/11779/domains/mysite.com/html/administrator/components/com_comprofiler/comprofiler.class.php on line 359

Warning: Invalid argument supplied for foreach() in /nfs/c01/h13/mnt/11779/domains/mysite.com/html/administrator/components/com_comprofiler/comprofiler.class.php on line 370

Also, I want next, after registering (and every time they log in) to reroute the users to the page that is customized toward which user group they selected on the registration page; how?

The registration field can be a drop-down single select field with values group1, group2, etc.

Then based on selected value you can use CB Auto Actions as in the tutorial to add user to group you want.