I'm close enough with my previous coworkers that I have them interview me. It's nice, because sometimes I forget talking about something and they can remind me to talk about X, Y, Z because they are familiar with my work.
It seems like you are a college graduate but have enough relevant experience to ask those you have worked with before.
I concur with others, too, saying to interview at companies you are not too interested in. It's as close as you can get to reality. Also, if you do get offer(s) you can use those as leverage to an increase compensation for the companies you do want.
You have a lot of experience for someone just out of college - hopefully you interview at a company that recognizes your work. There are some companies where the interviewers just fires technical questions one after another, and do not care about your background. You may want to think twice about those companies before accepting.
There will probably be people who balk about wasting the time of your interviewers. To them...meh. Improve your workplace so that you are not on the list of 'non-interesting' companies. This would also give your company a chance to impress a candidate and possibly change their mind and take your offer...or it will reinforce their perception of your company.