All units are held by production and until the US starts using more natural gas, the royalties will be low if you do not own a large tract of land. As far as grouping together to demand a higher price, those days are over due to the fact that all the acreage that was leased is either already unitized and permitted by the Texas RRC. If you feel it is not a good deal, then don't go forward with the sale of your mineral rights, if you feel it is a fair market offer, then make a decision. There are other companies besides the one that approached you that purchase mineral and royalty interests. You should google a few and submit your info to them. Make it a bidding war against the companies. Whoever pays more and treats you best is the company I would deal with.