Where can I drop off a group on a charter bus

It really depends on what attractions the group is interested in. The best address to use is 111 Alamo Plaza (Opposite H&M), San Antonio, TX it is directly across the street from the staircase that takes you to river walk and walking distance to the Alamo

Before the Conversation Center

There are lots of access points so it certainly depends on where is convenient for the bus and the places the bus occupants are going to be visiting.

Almo plaza would be your best bet.

There is a place that has buses that actually stop and pick up people I believe if need be you can drop off people on a charter bus there they also have public places that you can pay to actually park the bus if need be you would just have to look it up once you get in the area

I'd second Alamo plaza. You can catch the Riverwalk right there and it's near a lot if the restaurants on that side.